From c307459b9d1fcb8bbf3ea5a4162979532322ef77 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:13 -0700 Subject: fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs that are interested in filtering between types of things. The "how" should be an internal detail made uninteresting to the LSMs. Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Scott Branden Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- fs/exec.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/exec.c b/fs/exec.c index a91003e28eaa..9233cd50dc4c 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -954,6 +954,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, { loff_t i_size, pos; ssize_t bytes = 0; + void *allocated = NULL; int ret; if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) @@ -977,8 +978,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, goto out; } - if (id != READING_FIRMWARE_PREALLOC_BUFFER) - *buf = vmalloc(i_size); + if (!*buf) + *buf = allocated = vmalloc(i_size); if (!*buf) { ret = -ENOMEM; goto out; @@ -1007,7 +1008,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, out_free: if (ret < 0) { - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { + if (allocated) { vfree(*buf); *buf = NULL; } -- cgit v1.2.3 From b89999d004931ab2e5123611ace7dab77328f8d6 Mon Sep 17 00:00:00 2001 From: Scott Branden Date: Fri, 2 Oct 2020 10:38:15 -0700 Subject: fs/kernel_read_file: Split into separate include file Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h include file. That header gets pulled in just about everywhere and doesn't really need functions not related to the general fs interface. Suggested-by: Christoph Hellwig Signed-off-by: Scott Branden Signed-off-by: Kees Cook Reviewed-by: Christoph Hellwig Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Greg Kroah-Hartman Acked-by: James Morris Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/main.c | 1 + fs/exec.c | 1 + include/linux/fs.h | 38 --------------------------- include/linux/ima.h | 1 + include/linux/kernel_read_file.h | 51 +++++++++++++++++++++++++++++++++++++ include/linux/security.h | 1 + kernel/kexec_file.c | 1 + kernel/module.c | 1 + security/integrity/digsig.c | 1 + security/integrity/ima/ima_fs.c | 1 + security/integrity/ima/ima_main.c | 1 + security/integrity/ima/ima_policy.c | 1 + security/loadpin/loadpin.c | 1 + security/security.c | 1 + security/selinux/hooks.c | 1 + 15 files changed, 64 insertions(+), 38 deletions(-) create mode 100644 include/linux/kernel_read_file.h (limited to 'fs') diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index b0ec2721f55d..8c6ea389afcf 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -12,6 +12,7 @@ #include #include +#include #include #include #include diff --git a/fs/exec.c b/fs/exec.c index 9233cd50dc4c..c454af329413 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -23,6 +23,7 @@ * formats. */ +#include #include #include #include diff --git a/include/linux/fs.h b/include/linux/fs.h index 3fb7af12d033..0885d53afb11 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2858,44 +2858,6 @@ static inline void i_readcount_inc(struct inode *inode) #endif extern int do_pipe_flags(int *, int); -/* This is a list of *what* is being read, not *how* nor *where*. */ -#define __kernel_read_file_id(id) \ - id(UNKNOWN, unknown) \ - id(FIRMWARE, firmware) \ - id(MODULE, kernel-module) \ - id(KEXEC_IMAGE, kexec-image) \ - id(KEXEC_INITRAMFS, kexec-initramfs) \ - id(POLICY, security-policy) \ - id(X509_CERTIFICATE, x509-certificate) \ - id(MAX_ID, ) - -#define __fid_enumify(ENUM, dummy) READING_ ## ENUM, -#define __fid_stringify(dummy, str) #str, - -enum kernel_read_file_id { - __kernel_read_file_id(__fid_enumify) -}; - -static const char * const kernel_read_file_str[] = { - __kernel_read_file_id(__fid_stringify) -}; - -static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) -{ - if ((unsigned)id >= READING_MAX_ID) - return kernel_read_file_str[READING_UNKNOWN]; - - return kernel_read_file_str[id]; -} - -extern int kernel_read_file(struct file *, void **, loff_t *, loff_t, - enum kernel_read_file_id); -extern int kernel_read_file_from_path(const char *, void **, loff_t *, loff_t, - enum kernel_read_file_id); -extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, loff_t, - enum kernel_read_file_id); -extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t, - enum kernel_read_file_id); extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *); ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos); extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *); diff --git a/include/linux/ima.h b/include/linux/ima.h index d15100de6cdd..64804f78408b 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -7,6 +7,7 @@ #ifndef _LINUX_IMA_H #define _LINUX_IMA_H +#include #include #include #include diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h new file mode 100644 index 000000000000..78cf3d7dc835 --- /dev/null +++ b/include/linux/kernel_read_file.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_KERNEL_READ_FILE_H +#define _LINUX_KERNEL_READ_FILE_H + +#include +#include + +/* This is a list of *what* is being read, not *how* nor *where*. */ +#define __kernel_read_file_id(id) \ + id(UNKNOWN, unknown) \ + id(FIRMWARE, firmware) \ + id(MODULE, kernel-module) \ + id(KEXEC_IMAGE, kexec-image) \ + id(KEXEC_INITRAMFS, kexec-initramfs) \ + id(POLICY, security-policy) \ + id(X509_CERTIFICATE, x509-certificate) \ + id(MAX_ID, ) + +#define __fid_enumify(ENUM, dummy) READING_ ## ENUM, +#define __fid_stringify(dummy, str) #str, + +enum kernel_read_file_id { + __kernel_read_file_id(__fid_enumify) +}; + +static const char * const kernel_read_file_str[] = { + __kernel_read_file_id(__fid_stringify) +}; + +static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) +{ + if ((unsigned int)id >= READING_MAX_ID) + return kernel_read_file_str[READING_UNKNOWN]; + + return kernel_read_file_str[id]; +} + +int kernel_read_file(struct file *file, + void **buf, loff_t *size, loff_t max_size, + enum kernel_read_file_id id); +int kernel_read_file_from_path(const char *path, + void **buf, loff_t *size, loff_t max_size, + enum kernel_read_file_id id); +int kernel_read_file_from_path_initns(const char *path, + void **buf, loff_t *size, loff_t max_size, + enum kernel_read_file_id id); +int kernel_read_file_from_fd(int fd, + void **buf, loff_t *size, loff_t max_size, + enum kernel_read_file_id id); + +#endif /* _LINUX_KERNEL_READ_FILE_H */ diff --git a/include/linux/security.h b/include/linux/security.h index 0a0a03b36a3b..42df0d9b4c37 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -23,6 +23,7 @@ #ifndef __LINUX_SECURITY_H #define __LINUX_SECURITY_H +#include #include #include #include diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index ca40bef75a61..1cc82557f4c1 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include "kexec_internal.h" diff --git a/kernel/module.c b/kernel/module.c index b2808acac46b..4218abd272ee 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index ac02b7632353..f8869be45d8f 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 15a44c5022f7..e13ffece3726 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -13,6 +13,7 @@ */ #include +#include #include #include #include diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2f187784c5bc..5f89970c5ab7 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index b4de33074b37..3b0b43e18ecf 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -9,6 +9,7 @@ #include #include +#include #include #include #include diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c index 670a1aebb8a1..163c48216d13 100644 --- a/security/loadpin/loadpin.c +++ b/security/loadpin/loadpin.c @@ -11,6 +11,7 @@ #include #include +#include #include #include #include diff --git a/security/security.c b/security/security.c index 70a7ad357bc6..19d3150f68f4 100644 --- a/security/security.c +++ b/security/security.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a340986aa92e..96f5f8b3b9f0 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include -- cgit v1.2.3 From 5287b07f6d7cc366528954e2c3cae22e47cb76a4 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:16 -0700 Subject: fs/kernel_read_file: Split into separate source file These routines are used in places outside of exec(2), so in preparation for refactoring them, move them into a separate source file, fs/kernel_read_file.c. Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Acked-by: Scott Branden Link: https://lore.kernel.org/r/20201002173828.2099543-5-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- fs/Makefile | 3 +- fs/exec.c | 132 ----------------------------------------------- fs/kernel_read_file.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 140 insertions(+), 133 deletions(-) create mode 100644 fs/kernel_read_file.c (limited to 'fs') diff --git a/fs/Makefile b/fs/Makefile index 1c7b0e3f6daa..40c19ff3d570 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -13,7 +13,8 @@ obj-y := open.o read_write.o file_table.o super.o \ seq_file.o xattr.o libfs.o fs-writeback.o \ pnode.o splice.o sync.o utimes.o d_path.o \ stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \ - fs_types.o fs_context.o fs_parser.o fsopen.o init.o + fs_types.o fs_context.o fs_parser.o fsopen.o init.o \ + kernel_read_file.o ifeq ($(CONFIG_BLOCK),y) obj-y += buffer.o block_dev.o direct-io.o mpage.o diff --git a/fs/exec.c b/fs/exec.c index c454af329413..9f094406ea82 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -950,138 +950,6 @@ struct file *open_exec(const char *name) } EXPORT_SYMBOL(open_exec); -int kernel_read_file(struct file *file, void **buf, loff_t *size, - loff_t max_size, enum kernel_read_file_id id) -{ - loff_t i_size, pos; - ssize_t bytes = 0; - void *allocated = NULL; - int ret; - - if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) - return -EINVAL; - - ret = deny_write_access(file); - if (ret) - return ret; - - ret = security_kernel_read_file(file, id); - if (ret) - goto out; - - i_size = i_size_read(file_inode(file)); - if (i_size <= 0) { - ret = -EINVAL; - goto out; - } - if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) { - ret = -EFBIG; - goto out; - } - - if (!*buf) - *buf = allocated = vmalloc(i_size); - if (!*buf) { - ret = -ENOMEM; - goto out; - } - - pos = 0; - while (pos < i_size) { - bytes = kernel_read(file, *buf + pos, i_size - pos, &pos); - if (bytes < 0) { - ret = bytes; - goto out_free; - } - - if (bytes == 0) - break; - } - - if (pos != i_size) { - ret = -EIO; - goto out_free; - } - - ret = security_kernel_post_read_file(file, *buf, i_size, id); - if (!ret) - *size = pos; - -out_free: - if (ret < 0) { - if (allocated) { - vfree(*buf); - *buf = NULL; - } - } - -out: - allow_write_access(file); - return ret; -} -EXPORT_SYMBOL_GPL(kernel_read_file); - -int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, - loff_t max_size, enum kernel_read_file_id id) -{ - struct file *file; - int ret; - - if (!path || !*path) - return -EINVAL; - - file = filp_open(path, O_RDONLY, 0); - if (IS_ERR(file)) - return PTR_ERR(file); - - ret = kernel_read_file(file, buf, size, max_size, id); - fput(file); - return ret; -} -EXPORT_SYMBOL_GPL(kernel_read_file_from_path); - -int kernel_read_file_from_path_initns(const char *path, void **buf, - loff_t *size, loff_t max_size, - enum kernel_read_file_id id) -{ - struct file *file; - struct path root; - int ret; - - if (!path || !*path) - return -EINVAL; - - task_lock(&init_task); - get_fs_root(init_task.fs, &root); - task_unlock(&init_task); - - file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0); - path_put(&root); - if (IS_ERR(file)) - return PTR_ERR(file); - - ret = kernel_read_file(file, buf, size, max_size, id); - fput(file); - return ret; -} -EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); - -int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, - enum kernel_read_file_id id) -{ - struct fd f = fdget(fd); - int ret = -EBADF; - - if (!f.file) - goto out; - - ret = kernel_read_file(f.file, buf, size, max_size, id); -out: - fdput(f); - return ret; -} -EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); - #if defined(CONFIG_HAVE_AOUT) || defined(CONFIG_BINFMT_FLAT) || \ defined(CONFIG_BINFMT_ELF_FDPIC) ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len) diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c new file mode 100644 index 000000000000..54d972d4befc --- /dev/null +++ b/fs/kernel_read_file.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include + +int kernel_read_file(struct file *file, void **buf, loff_t *size, + loff_t max_size, enum kernel_read_file_id id) +{ + loff_t i_size, pos; + ssize_t bytes = 0; + void *allocated = NULL; + int ret; + + if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) + return -EINVAL; + + ret = deny_write_access(file); + if (ret) + return ret; + + ret = security_kernel_read_file(file, id); + if (ret) + goto out; + + i_size = i_size_read(file_inode(file)); + if (i_size <= 0) { + ret = -EINVAL; + goto out; + } + if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) { + ret = -EFBIG; + goto out; + } + + if (!*buf) + *buf = allocated = vmalloc(i_size); + if (!*buf) { + ret = -ENOMEM; + goto out; + } + + pos = 0; + while (pos < i_size) { + bytes = kernel_read(file, *buf + pos, i_size - pos, &pos); + if (bytes < 0) { + ret = bytes; + goto out_free; + } + + if (bytes == 0) + break; + } + + if (pos != i_size) { + ret = -EIO; + goto out_free; + } + + ret = security_kernel_post_read_file(file, *buf, i_size, id); + if (!ret) + *size = pos; + +out_free: + if (ret < 0) { + if (allocated) { + vfree(*buf); + *buf = NULL; + } + } + +out: + allow_write_access(file); + return ret; +} +EXPORT_SYMBOL_GPL(kernel_read_file); + +int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, + loff_t max_size, enum kernel_read_file_id id) +{ + struct file *file; + int ret; + + if (!path || !*path) + return -EINVAL; + + file = filp_open(path, O_RDONLY, 0); + if (IS_ERR(file)) + return PTR_ERR(file); + + ret = kernel_read_file(file, buf, size, max_size, id); + fput(file); + return ret; +} +EXPORT_SYMBOL_GPL(kernel_read_file_from_path); + +int kernel_read_file_from_path_initns(const char *path, void **buf, + loff_t *size, loff_t max_size, + enum kernel_read_file_id id) +{ + struct file *file; + struct path root; + int ret; + + if (!path || !*path) + return -EINVAL; + + task_lock(&init_task); + get_fs_root(init_task.fs, &root); + task_unlock(&init_task); + + file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0); + path_put(&root); + if (IS_ERR(file)) + return PTR_ERR(file); + + ret = kernel_read_file(file, buf, size, max_size, id); + fput(file); + return ret; +} +EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); + +int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, + enum kernel_read_file_id id) +{ + struct fd f = fdget(fd); + int ret = -EBADF; + + if (!f.file) + goto out; + + ret = kernel_read_file(f.file, buf, size, max_size, id); +out: + fdput(f); + return ret; +} +EXPORT_SYMBOL_GPL(kernel_read_file_from_fd); -- cgit v1.2.3 From f7a4f689bca6072492626938aad6dd2f32c5bf97 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:17 -0700 Subject: fs/kernel_read_file: Remove redundant size argument In preparation for refactoring kernel_read_file*(), remove the redundant "size" argument which is not needed: it can be included in the return code, with callers adjusted. (VFS reads already cannot be larger than INT_MAX.) Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Reviewed-by: James Morris Acked-by: Scott Branden Link: https://lore.kernel.org/r/20201002173828.2099543-6-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/main.c | 10 ++++++---- fs/kernel_read_file.c | 20 +++++++++----------- include/linux/kernel_read_file.h | 8 ++++---- kernel/kexec_file.c | 14 +++++++------- kernel/module.c | 7 +++---- security/integrity/digsig.c | 5 +++-- security/integrity/ima/ima_fs.c | 6 ++++-- 7 files changed, 36 insertions(+), 34 deletions(-) (limited to 'fs') diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index 8c6ea389afcf..6df1bdcfeb9d 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -467,7 +467,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, size_t in_size, const void *in_buffer)) { - loff_t size; + size_t size; int i, len; int rc = -ENOENT; char *path; @@ -499,10 +499,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, fw_priv->size = 0; /* load firmware files from the mount namespace of init */ - rc = kernel_read_file_from_path_initns(path, &buffer, - &size, msize, + rc = kernel_read_file_from_path_initns(path, &buffer, msize, READING_FIRMWARE); - if (rc) { + if (rc < 0) { if (rc != -ENOENT) dev_warn(device, "loading %s failed with error %d\n", path, rc); @@ -511,6 +510,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, path); continue; } + size = rc; + rc = 0; + dev_dbg(device, "Loading firmware from %s\n", path); if (decompress) { dev_dbg(device, "f/w decompressing %s\n", diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index 54d972d4befc..dc28a8def597 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -5,7 +5,7 @@ #include #include -int kernel_read_file(struct file *file, void **buf, loff_t *size, +int kernel_read_file(struct file *file, void **buf, loff_t max_size, enum kernel_read_file_id id) { loff_t i_size, pos; @@ -29,7 +29,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, ret = -EINVAL; goto out; } - if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) { + if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) { ret = -EFBIG; goto out; } @@ -59,8 +59,6 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, } ret = security_kernel_post_read_file(file, *buf, i_size, id); - if (!ret) - *size = pos; out_free: if (ret < 0) { @@ -72,11 +70,11 @@ out_free: out: allow_write_access(file); - return ret; + return ret == 0 ? pos : ret; } EXPORT_SYMBOL_GPL(kernel_read_file); -int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, +int kernel_read_file_from_path(const char *path, void **buf, loff_t max_size, enum kernel_read_file_id id) { struct file *file; @@ -89,14 +87,14 @@ int kernel_read_file_from_path(const char *path, void **buf, loff_t *size, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, size, max_size, id); + ret = kernel_read_file(file, buf, max_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path); int kernel_read_file_from_path_initns(const char *path, void **buf, - loff_t *size, loff_t max_size, + loff_t max_size, enum kernel_read_file_id id) { struct file *file; @@ -115,13 +113,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, size, max_size, id); + ret = kernel_read_file(file, buf, max_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); -int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, +int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size, enum kernel_read_file_id id) { struct fd f = fdget(fd); @@ -130,7 +128,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size, if (!f.file) goto out; - ret = kernel_read_file(f.file, buf, size, max_size, id); + ret = kernel_read_file(f.file, buf, max_size, id); out: fdput(f); return ret; diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h index 78cf3d7dc835..0ca0bdbed1bd 100644 --- a/include/linux/kernel_read_file.h +++ b/include/linux/kernel_read_file.h @@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) } int kernel_read_file(struct file *file, - void **buf, loff_t *size, loff_t max_size, + void **buf, loff_t max_size, enum kernel_read_file_id id); int kernel_read_file_from_path(const char *path, - void **buf, loff_t *size, loff_t max_size, + void **buf, loff_t max_size, enum kernel_read_file_id id); int kernel_read_file_from_path_initns(const char *path, - void **buf, loff_t *size, loff_t max_size, + void **buf, loff_t max_size, enum kernel_read_file_id id); int kernel_read_file_from_fd(int fd, - void **buf, loff_t *size, loff_t max_size, + void **buf, loff_t max_size, enum kernel_read_file_id id); #endif /* _LINUX_KERNEL_READ_FILE_H */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 1cc82557f4c1..b20cfde8a01d 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -220,13 +220,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, { int ret; void *ldata; - loff_t size; ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, - &size, INT_MAX, READING_KEXEC_IMAGE); - if (ret) + INT_MAX, READING_KEXEC_IMAGE); + if (ret < 0) return ret; - image->kernel_buf_len = size; + image->kernel_buf_len = ret; /* Call arch image probe handlers */ ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, @@ -243,11 +242,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, - &size, INT_MAX, + INT_MAX, READING_KEXEC_INITRAMFS); - if (ret) + if (ret < 0) goto out; - image->initrd_buf_len = size; + image->initrd_buf_len = ret; + ret = 0; } if (cmdline_len) { diff --git a/kernel/module.c b/kernel/module.c index 4218abd272ee..9faa6322f17b 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4035,7 +4035,6 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { struct load_info info = { }; - loff_t size; void *hdr = NULL; int err; @@ -4049,12 +4048,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) |MODULE_INIT_IGNORE_VERMAGIC)) return -EINVAL; - err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX, + err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, READING_MODULE); - if (err) + if (err < 0) return err; info.hdr = hdr; - info.len = size; + info.len = err; return load_module(&info, uargs, flags); } diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index f8869be45d8f..97661ffabc4e 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -171,16 +171,17 @@ int __init integrity_add_key(const unsigned int id, const void *data, int __init integrity_load_x509(const unsigned int id, const char *path) { void *data = NULL; - loff_t size; + size_t size; int rc; key_perm_t perm; - rc = kernel_read_file_from_path(path, &data, &size, 0, + rc = kernel_read_file_from_path(path, &data, 0, READING_X509_CERTIFICATE); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); return rc; } + size = rc; perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ; diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index e13ffece3726..602f52717757 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -275,7 +275,7 @@ static ssize_t ima_read_policy(char *path) { void *data = NULL; char *datap; - loff_t size; + size_t size; int rc, pathlen = strlen(path); char *p; @@ -284,11 +284,13 @@ static ssize_t ima_read_policy(char *path) datap = path; strsep(&datap, "\n"); - rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY); + rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); return rc; } + size = rc; + rc = 0; datap = data; while (size > 0 && (p = strsep(&datap, "\n"))) { -- cgit v1.2.3 From 113eeb517780add2b38932a61d4e4440a73eb72a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:18 -0700 Subject: fs/kernel_read_file: Switch buffer size arg to size_t In preparation for further refactoring of kernel_read_file*(), rename the "max_size" argument to the more accurate "buf_size", and correct its type to size_t. Add kerndoc to explain the specifics of how the arguments will be used. Note that with buf_size now size_t, it can no longer be negative (and was never called with a negative value). Adjust callers to use it as a "maximum size" when *buf is NULL. Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Reviewed-by: James Morris Acked-by: Scott Branden Link: https://lore.kernel.org/r/20201002173828.2099543-7-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- fs/kernel_read_file.c | 34 +++++++++++++++++++++++++--------- include/linux/kernel_read_file.h | 8 ++++---- security/integrity/digsig.c | 2 +- security/integrity/ima/ima_fs.c | 2 +- 4 files changed, 31 insertions(+), 15 deletions(-) (limited to 'fs') diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index dc28a8def597..e21a76001fff 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -5,15 +5,31 @@ #include #include +/** + * kernel_read_file() - read file contents into a kernel buffer + * + * @file file to read from + * @buf pointer to a "void *" buffer for reading into (if + * *@buf is NULL, a buffer will be allocated, and + * @buf_size will be ignored) + * @buf_size size of buf, if already allocated. If @buf not + * allocated, this is the largest size to allocate. + * @id the kernel_read_file_id identifying the type of + * file contents being read (for LSMs to examine) + * + * Returns number of bytes read (no single read will be bigger + * than INT_MAX), or negative on error. + * + */ int kernel_read_file(struct file *file, void **buf, - loff_t max_size, enum kernel_read_file_id id) + size_t buf_size, enum kernel_read_file_id id) { loff_t i_size, pos; ssize_t bytes = 0; void *allocated = NULL; int ret; - if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) + if (!S_ISREG(file_inode(file)->i_mode)) return -EINVAL; ret = deny_write_access(file); @@ -29,7 +45,7 @@ int kernel_read_file(struct file *file, void **buf, ret = -EINVAL; goto out; } - if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) { + if (i_size > INT_MAX || i_size > buf_size) { ret = -EFBIG; goto out; } @@ -75,7 +91,7 @@ out: EXPORT_SYMBOL_GPL(kernel_read_file); int kernel_read_file_from_path(const char *path, void **buf, - loff_t max_size, enum kernel_read_file_id id) + size_t buf_size, enum kernel_read_file_id id) { struct file *file; int ret; @@ -87,14 +103,14 @@ int kernel_read_file_from_path(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, max_size, id); + ret = kernel_read_file(file, buf, buf_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path); int kernel_read_file_from_path_initns(const char *path, void **buf, - loff_t max_size, + size_t buf_size, enum kernel_read_file_id id) { struct file *file; @@ -113,13 +129,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, max_size, id); + ret = kernel_read_file(file, buf, buf_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); -int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size, +int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, enum kernel_read_file_id id) { struct fd f = fdget(fd); @@ -128,7 +144,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size, if (!f.file) goto out; - ret = kernel_read_file(f.file, buf, max_size, id); + ret = kernel_read_file(f.file, buf, buf_size, id); out: fdput(f); return ret; diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h index 0ca0bdbed1bd..910039e7593e 100644 --- a/include/linux/kernel_read_file.h +++ b/include/linux/kernel_read_file.h @@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) } int kernel_read_file(struct file *file, - void **buf, loff_t max_size, + void **buf, size_t buf_size, enum kernel_read_file_id id); int kernel_read_file_from_path(const char *path, - void **buf, loff_t max_size, + void **buf, size_t buf_size, enum kernel_read_file_id id); int kernel_read_file_from_path_initns(const char *path, - void **buf, loff_t max_size, + void **buf, size_t buf_size, enum kernel_read_file_id id); int kernel_read_file_from_fd(int fd, - void **buf, loff_t max_size, + void **buf, size_t buf_size, enum kernel_read_file_id id); #endif /* _LINUX_KERNEL_READ_FILE_H */ diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 97661ffabc4e..04f779c4f5ed 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path) int rc; key_perm_t perm; - rc = kernel_read_file_from_path(path, &data, 0, + rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_X509_CERTIFICATE); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 602f52717757..692b83e82edf 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -284,7 +284,7 @@ static ssize_t ima_read_policy(char *path) datap = path; strsep(&datap, "\n"); - rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY); + rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_POLICY); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); return rc; -- cgit v1.2.3 From 885352881f11f1f3113d8eb877786bcb6d720544 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:19 -0700 Subject: fs/kernel_read_file: Add file_size output argument In preparation for adding partial read support, add an optional output argument to kernel_read_file*() that reports the file size so callers can reason more easily about their reading progress. Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Reviewed-by: Luis Chamberlain Reviewed-by: James Morris Acked-by: Scott Branden Link: https://lore.kernel.org/r/20201002173828.2099543-8-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/main.c | 1 + fs/kernel_read_file.c | 19 +++++++++++++------ include/linux/kernel_read_file.h | 4 ++++ kernel/kexec_file.c | 4 ++-- kernel/module.c | 2 +- security/integrity/digsig.c | 2 +- security/integrity/ima/ima_fs.c | 2 +- 7 files changed, 23 insertions(+), 11 deletions(-) (limited to 'fs') diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index 6df1bdcfeb9d..d9a180148c4b 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -500,6 +500,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, /* load firmware files from the mount namespace of init */ rc = kernel_read_file_from_path_initns(path, &buffer, msize, + NULL, READING_FIRMWARE); if (rc < 0) { if (rc != -ENOENT) diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index e21a76001fff..2e29c38eb4df 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -14,6 +14,8 @@ * @buf_size will be ignored) * @buf_size size of buf, if already allocated. If @buf not * allocated, this is the largest size to allocate. + * @file_size if non-NULL, the full size of @file will be + * written here. * @id the kernel_read_file_id identifying the type of * file contents being read (for LSMs to examine) * @@ -22,7 +24,8 @@ * */ int kernel_read_file(struct file *file, void **buf, - size_t buf_size, enum kernel_read_file_id id) + size_t buf_size, size_t *file_size, + enum kernel_read_file_id id) { loff_t i_size, pos; ssize_t bytes = 0; @@ -49,6 +52,8 @@ int kernel_read_file(struct file *file, void **buf, ret = -EFBIG; goto out; } + if (file_size) + *file_size = i_size; if (!*buf) *buf = allocated = vmalloc(i_size); @@ -91,7 +96,8 @@ out: EXPORT_SYMBOL_GPL(kernel_read_file); int kernel_read_file_from_path(const char *path, void **buf, - size_t buf_size, enum kernel_read_file_id id) + size_t buf_size, size_t *file_size, + enum kernel_read_file_id id) { struct file *file; int ret; @@ -103,14 +109,14 @@ int kernel_read_file_from_path(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, buf_size, id); + ret = kernel_read_file(file, buf, buf_size, file_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path); int kernel_read_file_from_path_initns(const char *path, void **buf, - size_t buf_size, + size_t buf_size, size_t *file_size, enum kernel_read_file_id id) { struct file *file; @@ -129,13 +135,14 @@ int kernel_read_file_from_path_initns(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, buf_size, id); + ret = kernel_read_file(file, buf, buf_size, file_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id) { struct fd f = fdget(fd); @@ -144,7 +151,7 @@ int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, if (!f.file) goto out; - ret = kernel_read_file(f.file, buf, buf_size, id); + ret = kernel_read_file(f.file, buf, buf_size, file_size, id); out: fdput(f); return ret; diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h index 910039e7593e..023293eaf948 100644 --- a/include/linux/kernel_read_file.h +++ b/include/linux/kernel_read_file.h @@ -37,15 +37,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) int kernel_read_file(struct file *file, void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id); int kernel_read_file_from_path(const char *path, void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id); int kernel_read_file_from_path_initns(const char *path, void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id); int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id); #endif /* _LINUX_KERNEL_READ_FILE_H */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index b20cfde8a01d..ee51c1028658 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -222,7 +222,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, void *ldata; ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, - INT_MAX, READING_KEXEC_IMAGE); + INT_MAX, NULL, READING_KEXEC_IMAGE); if (ret < 0) return ret; image->kernel_buf_len = ret; @@ -242,7 +242,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, - INT_MAX, + INT_MAX, NULL, READING_KEXEC_INITRAMFS); if (ret < 0) goto out; diff --git a/kernel/module.c b/kernel/module.c index 9faa6322f17b..0f11eaed047e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4048,7 +4048,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) |MODULE_INIT_IGNORE_VERMAGIC)) return -EINVAL; - err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, + err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, NULL, READING_MODULE); if (err < 0) return err; diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 04f779c4f5ed..8a523dfd7fd7 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path) int rc; key_perm_t perm; - rc = kernel_read_file_from_path(path, &data, INT_MAX, + rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_X509_CERTIFICATE); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 692b83e82edf..5fc56ccb6678 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -284,7 +284,7 @@ static ssize_t ima_read_policy(char *path) datap = path; strsep(&datap, "\n"); - rc = kernel_read_file_from_path(path, &data, INT_MAX, READING_POLICY); + rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_POLICY); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); return rc; -- cgit v1.2.3 From 2039bda1fa8dad3f4275b29eeaffef545bcbc85d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:23 -0700 Subject: LSM: Add "contents" flag to kernel_read_file hook As with the kernel_load_data LSM hook, add a "contents" flag to the kernel_read_file LSM hook that indicates whether the LSM can expect a matching call to the kernel_post_read_file LSM hook with the full contents of the file. With the coming addition of partial file read support for kernel_read_file*() API, the LSM will no longer be able to always see the entire contents of a file during the read calls. For cases where the LSM must read examine the complete file contents, it will need to do so on its own every time the kernel_read_file hook is called with contents=false (or reject such cases). Adjust all existing LSMs to retain existing behavior. Signed-off-by: Kees Cook Reviewed-by: Mimi Zohar Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- fs/kernel_read_file.c | 2 +- include/linux/ima.h | 6 ++++-- include/linux/lsm_hook_defs.h | 2 +- include/linux/lsm_hooks.h | 3 +++ include/linux/security.h | 6 ++++-- security/integrity/ima/ima_main.c | 10 +++++++++- security/loadpin/loadpin.c | 14 ++++++++++++-- security/security.c | 7 ++++--- security/selinux/hooks.c | 5 +++-- 9 files changed, 41 insertions(+), 14 deletions(-) (limited to 'fs') diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index 2e29c38eb4df..d73bc3fa710a 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -39,7 +39,7 @@ int kernel_read_file(struct file *file, void **buf, if (ret) return ret; - ret = security_kernel_read_file(file, id); + ret = security_kernel_read_file(file, id, true); if (ret) goto out; diff --git a/include/linux/ima.h b/include/linux/ima.h index af9fb8c5f16a..8fa7bcfb2da2 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -23,7 +23,8 @@ extern int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot); extern int ima_load_data(enum kernel_load_data_id id, bool contents); extern int ima_post_load_data(char *buf, loff_t size, enum kernel_load_data_id id, char *description); -extern int ima_read_file(struct file *file, enum kernel_read_file_id id); +extern int ima_read_file(struct file *file, enum kernel_read_file_id id, + bool contents); extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); @@ -92,7 +93,8 @@ static inline int ima_post_load_data(char *buf, loff_t size, return 0; } -static inline int ima_read_file(struct file *file, enum kernel_read_file_id id) +static inline int ima_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) { return 0; } diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 83c6f1f5cc1e..d67cb3502310 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -188,7 +188,7 @@ LSM_HOOK(int, 0, kernel_load_data, enum kernel_load_data_id id, bool contents) LSM_HOOK(int, 0, kernel_post_load_data, char *buf, loff_t size, enum kernel_read_file_id id, char *description) LSM_HOOK(int, 0, kernel_read_file, struct file *file, - enum kernel_read_file_id id) + enum kernel_read_file_id id, bool contents) LSM_HOOK(int, 0, kernel_post_read_file, struct file *file, char *buf, loff_t size, enum kernel_read_file_id id) LSM_HOOK(int, 0, task_fix_setuid, struct cred *new, const struct cred *old, diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 6bb4f1a0158c..8814e3d5952d 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -651,6 +651,7 @@ * @file contains the file structure pointing to the file being read * by the kernel. * @id kernel read file identifier + * @contents if a subsequent @kernel_post_read_file will be called. * Return 0 if permission is granted. * @kernel_post_read_file: * Read a file specified by userspace. @@ -659,6 +660,8 @@ * @buf pointer to buffer containing the file contents. * @size length of the file contents. * @id kernel read file identifier + * This must be paired with a prior @kernel_read_file call that had + * @contents set to true. * Return 0 if permission is granted. * @task_fix_setuid: * Update the module's state after setting one or more of the user diff --git a/include/linux/security.h b/include/linux/security.h index 51c8e4e6b7cc..bc2725491560 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -391,7 +391,8 @@ int security_kernel_load_data(enum kernel_load_data_id id, bool contents); int security_kernel_post_load_data(char *buf, loff_t size, enum kernel_load_data_id id, char *description); -int security_kernel_read_file(struct file *file, enum kernel_read_file_id id); +int security_kernel_read_file(struct file *file, enum kernel_read_file_id id, + bool contents); int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, enum kernel_read_file_id id); int security_task_fix_setuid(struct cred *new, const struct cred *old, @@ -1030,7 +1031,8 @@ static inline int security_kernel_post_load_data(char *buf, loff_t size, } static inline int security_kernel_read_file(struct file *file, - enum kernel_read_file_id id) + enum kernel_read_file_id id, + bool contents) { return 0; } diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 6f2b8352573a..939f53d02627 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -602,6 +602,7 @@ void ima_post_path_mknod(struct dentry *dentry) * ima_read_file - pre-measure/appraise hook decision based on policy * @file: pointer to the file to be measured/appraised/audit * @read_id: caller identifier + * @contents: whether a subsequent call will be made to ima_post_read_file() * * Permit reading a file based on policy. The policy rules are written * in terms of the policy identifier. Appraising the integrity of @@ -609,8 +610,15 @@ void ima_post_path_mknod(struct dentry *dentry) * * For permission return 0, otherwise return -EACCES. */ -int ima_read_file(struct file *file, enum kernel_read_file_id read_id) +int ima_read_file(struct file *file, enum kernel_read_file_id read_id, + bool contents) { + /* Reject all partial reads during appraisal. */ + if (!contents) { + if (ima_appraise & IMA_APPRAISE_ENFORCE) + return -EACCES; + } + /* * Do devices using pre-allocated memory run the risk of the * firmware being accessible to the device prior to the completion diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c index 28782412febb..b12f7d986b1e 100644 --- a/security/loadpin/loadpin.c +++ b/security/loadpin/loadpin.c @@ -118,11 +118,21 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb) } } -static int loadpin_read_file(struct file *file, enum kernel_read_file_id id) +static int loadpin_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) { struct super_block *load_root; const char *origin = kernel_read_file_id_str(id); + /* + * If we will not know that we'll be seeing the full contents + * then we cannot trust a load will be complete and unchanged + * off disk. Treat all contents=false hooks as if there were + * no associated file struct. + */ + if (!contents) + file = NULL; + /* If the file id is excluded, ignore the pinning. */ if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) && ignore_read_file_id[id]) { @@ -179,7 +189,7 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id) static int loadpin_load_data(enum kernel_load_data_id id, bool contents) { - return loadpin_read_file(NULL, (enum kernel_read_file_id) id); + return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents); } static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = { diff --git a/security/security.c b/security/security.c index 531b855826fc..a28045dc9e7f 100644 --- a/security/security.c +++ b/security/security.c @@ -1672,14 +1672,15 @@ int security_kernel_module_request(char *kmod_name) return integrity_kernel_module_request(kmod_name); } -int security_kernel_read_file(struct file *file, enum kernel_read_file_id id) +int security_kernel_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) { int ret; - ret = call_int_hook(kernel_read_file, 0, file, id); + ret = call_int_hook(kernel_read_file, 0, file, id, contents); if (ret) return ret; - return ima_read_file(file, id); + return ima_read_file(file, id, contents); } EXPORT_SYMBOL_GPL(security_kernel_read_file); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 558beee97d8d..dec654d52b68 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4003,13 +4003,14 @@ static int selinux_kernel_module_from_file(struct file *file) } static int selinux_kernel_read_file(struct file *file, - enum kernel_read_file_id id) + enum kernel_read_file_id id, + bool contents) { int rc = 0; switch (id) { case READING_MODULE: - rc = selinux_kernel_module_from_file(file); + rc = selinux_kernel_module_from_file(contents ? file : NULL); break; default: break; -- cgit v1.2.3 From 0fa8e084648779eeb8929ae004301b3acf3bad84 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 2 Oct 2020 10:38:25 -0700 Subject: fs/kernel_file_read: Add "offset" arg for partial reads To perform partial reads, callers of kernel_read_file*() must have a non-NULL file_size argument and a preallocated buffer. The new "offset" argument can then be used to seek to specific locations in the file to fill the buffer to, at most, "buf_size" per call. Where possible, the LSM hooks can report whether a full file has been read or not so that the contents can be reasoned about. Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20201002173828.2099543-14-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/firmware_loader/main.c | 2 +- fs/kernel_read_file.c | 78 +++++++++++++++++++++++++------------ include/linux/kernel_read_file.h | 8 ++-- kernel/kexec_file.c | 4 +- kernel/module.c | 2 +- security/integrity/digsig.c | 2 +- security/integrity/ima/ima_fs.c | 3 +- 7 files changed, 65 insertions(+), 34 deletions(-) (limited to 'fs') diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c index d9a180148c4b..79f86466d472 100644 --- a/drivers/base/firmware_loader/main.c +++ b/drivers/base/firmware_loader/main.c @@ -499,7 +499,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, fw_priv->size = 0; /* load firmware files from the mount namespace of init */ - rc = kernel_read_file_from_path_initns(path, &buffer, msize, + rc = kernel_read_file_from_path_initns(path, 0, &buffer, msize, NULL, READING_FIRMWARE); if (rc < 0) { diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index d73bc3fa710a..90d255fbdd9b 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -9,6 +9,7 @@ * kernel_read_file() - read file contents into a kernel buffer * * @file file to read from + * @offset where to start reading from (see below). * @buf pointer to a "void *" buffer for reading into (if * *@buf is NULL, a buffer will be allocated, and * @buf_size will be ignored) @@ -19,19 +20,31 @@ * @id the kernel_read_file_id identifying the type of * file contents being read (for LSMs to examine) * + * @offset must be 0 unless both @buf and @file_size are non-NULL + * (i.e. the caller must be expecting to read partial file contents + * via an already-allocated @buf, in at most @buf_size chunks, and + * will be able to determine when the entire file was read by + * checking @file_size). This isn't a recommended way to read a + * file, though, since it is possible that the contents might + * change between calls to kernel_read_file(). + * * Returns number of bytes read (no single read will be bigger * than INT_MAX), or negative on error. * */ -int kernel_read_file(struct file *file, void **buf, +int kernel_read_file(struct file *file, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id) { loff_t i_size, pos; - ssize_t bytes = 0; + size_t copied; void *allocated = NULL; + bool whole_file; int ret; + if (offset != 0 && (!*buf || !file_size)) + return -EINVAL; + if (!S_ISREG(file_inode(file)->i_mode)) return -EINVAL; @@ -39,19 +52,27 @@ int kernel_read_file(struct file *file, void **buf, if (ret) return ret; - ret = security_kernel_read_file(file, id, true); - if (ret) - goto out; - i_size = i_size_read(file_inode(file)); if (i_size <= 0) { ret = -EINVAL; goto out; } - if (i_size > INT_MAX || i_size > buf_size) { + /* The file is too big for sane activities. */ + if (i_size > INT_MAX) { + ret = -EFBIG; + goto out; + } + /* The entire file cannot be read in one buffer. */ + if (!file_size && offset == 0 && i_size > buf_size) { ret = -EFBIG; goto out; } + + whole_file = (offset == 0 && i_size <= buf_size); + ret = security_kernel_read_file(file, id, whole_file); + if (ret) + goto out; + if (file_size) *file_size = i_size; @@ -62,9 +83,14 @@ int kernel_read_file(struct file *file, void **buf, goto out; } - pos = 0; - while (pos < i_size) { - bytes = kernel_read(file, *buf + pos, i_size - pos, &pos); + pos = offset; + copied = 0; + while (copied < buf_size) { + ssize_t bytes; + size_t wanted = min_t(size_t, buf_size - copied, + i_size - pos); + + bytes = kernel_read(file, *buf + copied, wanted, &pos); if (bytes < 0) { ret = bytes; goto out_free; @@ -72,14 +98,17 @@ int kernel_read_file(struct file *file, void **buf, if (bytes == 0) break; + copied += bytes; } - if (pos != i_size) { - ret = -EIO; - goto out_free; - } + if (whole_file) { + if (pos != i_size) { + ret = -EIO; + goto out_free; + } - ret = security_kernel_post_read_file(file, *buf, i_size, id); + ret = security_kernel_post_read_file(file, *buf, i_size, id); + } out_free: if (ret < 0) { @@ -91,11 +120,11 @@ out_free: out: allow_write_access(file); - return ret == 0 ? pos : ret; + return ret == 0 ? copied : ret; } EXPORT_SYMBOL_GPL(kernel_read_file); -int kernel_read_file_from_path(const char *path, void **buf, +int kernel_read_file_from_path(const char *path, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id) { @@ -109,14 +138,15 @@ int kernel_read_file_from_path(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, buf_size, file_size, id); + ret = kernel_read_file(file, offset, buf, buf_size, file_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path); -int kernel_read_file_from_path_initns(const char *path, void **buf, - size_t buf_size, size_t *file_size, +int kernel_read_file_from_path_initns(const char *path, loff_t offset, + void **buf, size_t buf_size, + size_t *file_size, enum kernel_read_file_id id) { struct file *file; @@ -135,14 +165,14 @@ int kernel_read_file_from_path_initns(const char *path, void **buf, if (IS_ERR(file)) return PTR_ERR(file); - ret = kernel_read_file(file, buf, buf_size, file_size, id); + ret = kernel_read_file(file, offset, buf, buf_size, file_size, id); fput(file); return ret; } EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns); -int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, - size_t *file_size, +int kernel_read_file_from_fd(int fd, loff_t offset, void **buf, + size_t buf_size, size_t *file_size, enum kernel_read_file_id id) { struct fd f = fdget(fd); @@ -151,7 +181,7 @@ int kernel_read_file_from_fd(int fd, void **buf, size_t buf_size, if (!f.file) goto out; - ret = kernel_read_file(f.file, buf, buf_size, file_size, id); + ret = kernel_read_file(f.file, offset, buf, buf_size, file_size, id); out: fdput(f); return ret; diff --git a/include/linux/kernel_read_file.h b/include/linux/kernel_read_file.h index 023293eaf948..575ffa1031d3 100644 --- a/include/linux/kernel_read_file.h +++ b/include/linux/kernel_read_file.h @@ -35,19 +35,19 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id) return kernel_read_file_str[id]; } -int kernel_read_file(struct file *file, +int kernel_read_file(struct file *file, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id); -int kernel_read_file_from_path(const char *path, +int kernel_read_file_from_path(const char *path, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id); -int kernel_read_file_from_path_initns(const char *path, +int kernel_read_file_from_path_initns(const char *path, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id); -int kernel_read_file_from_fd(int fd, +int kernel_read_file_from_fd(int fd, loff_t offset, void **buf, size_t buf_size, size_t *file_size, enum kernel_read_file_id id); diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index ee51c1028658..84f7316792a7 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -221,7 +221,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, int ret; void *ldata; - ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, + ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf, INT_MAX, NULL, READING_KEXEC_IMAGE); if (ret < 0) return ret; @@ -241,7 +241,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, #endif /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { - ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, + ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf, INT_MAX, NULL, READING_KEXEC_INITRAMFS); if (ret < 0) diff --git a/kernel/module.c b/kernel/module.c index adfa21dd3842..9c578e44abe7 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4054,7 +4054,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) |MODULE_INIT_IGNORE_VERMAGIC)) return -EINVAL; - err = kernel_read_file_from_fd(fd, &hdr, INT_MAX, NULL, + err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL, READING_MODULE); if (err < 0) return err; diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 8a523dfd7fd7..0f518dcfde05 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -175,7 +175,7 @@ int __init integrity_load_x509(const unsigned int id, const char *path) int rc; key_perm_t perm; - rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, + rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL, READING_X509_CERTIFICATE); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index 5fc56ccb6678..ea8ff8a07b36 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -284,7 +284,8 @@ static ssize_t ima_read_policy(char *path) datap = path; strsep(&datap, "\n"); - rc = kernel_read_file_from_path(path, &data, INT_MAX, NULL, READING_POLICY); + rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL, + READING_POLICY); if (rc < 0) { pr_err("Unable to open file: %s (%d)", path, rc); return rc; -- cgit v1.2.3