From 916cc5167cc6f81651f4460d9a35c939ad18ecff Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 21 Mar 2024 09:36:32 -0700 Subject: lib: code tagging framework MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add basic infrastructure to support code tagging which stores tag common information consisting of the module name, function, file name and line number. Provide functions to register a new code tag type and navigate between code tags. Link: https://lkml.kernel.org/r/20240321163705.3067592-11-surenb@google.com Co-developed-by: Kent Overstreet Signed-off-by: Kent Overstreet Signed-off-by: Suren Baghdasaryan Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton --- include/linux/codetag.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 include/linux/codetag.h (limited to 'include/linux/codetag.h') diff --git a/include/linux/codetag.h b/include/linux/codetag.h new file mode 100644 index 000000000000..7734269cdb63 --- /dev/null +++ b/include/linux/codetag.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * code tagging framework + */ +#ifndef _LINUX_CODETAG_H +#define _LINUX_CODETAG_H + +#include + +struct codetag_iterator; +struct codetag_type; +struct codetag_module; +struct seq_buf; +struct module; + +/* + * An instance of this structure is created in a special ELF section at every + * code location being tagged. At runtime, the special section is treated as + * an array of these. + */ +struct codetag { + unsigned int flags; /* used in later patches */ + unsigned int lineno; + const char *modname; + const char *function; + const char *filename; +} __aligned(8); + +union codetag_ref { + struct codetag *ct; +}; + +struct codetag_type_desc { + const char *section; + size_t tag_size; +}; + +struct codetag_iterator { + struct codetag_type *cttype; + struct codetag_module *cmod; + unsigned long mod_id; + struct codetag *ct; +}; + +#ifdef MODULE +#define CT_MODULE_NAME KBUILD_MODNAME +#else +#define CT_MODULE_NAME NULL +#endif + +#define CODE_TAG_INIT { \ + .modname = CT_MODULE_NAME, \ + .function = __func__, \ + .filename = __FILE__, \ + .lineno = __LINE__, \ + .flags = 0, \ +} + +void codetag_lock_module_list(struct codetag_type *cttype, bool lock); +struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype); +struct codetag *codetag_next_ct(struct codetag_iterator *iter); + +void codetag_to_text(struct seq_buf *out, struct codetag *ct); + +struct codetag_type * +codetag_register_type(const struct codetag_type_desc *desc); + +#endif /* _LINUX_CODETAG_H */ -- cgit v1.2.3 From a473573964e51dcb6efc182f773cd3924be4a184 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 21 Mar 2024 09:36:33 -0700 Subject: lib: code tagging module support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support for code tagging from dynamically loaded modules. Link: https://lkml.kernel.org/r/20240321163705.3067592-12-surenb@google.com Signed-off-by: Suren Baghdasaryan Co-developed-by: Kent Overstreet Signed-off-by: Kent Overstreet Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton --- include/linux/codetag.h | 12 ++++++++++ kernel/module/main.c | 4 ++++ lib/codetag.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 72 insertions(+), 2 deletions(-) (limited to 'include/linux/codetag.h') diff --git a/include/linux/codetag.h b/include/linux/codetag.h index 7734269cdb63..c44f5b83f24d 100644 --- a/include/linux/codetag.h +++ b/include/linux/codetag.h @@ -33,6 +33,10 @@ union codetag_ref { struct codetag_type_desc { const char *section; size_t tag_size; + void (*module_load)(struct codetag_type *cttype, + struct codetag_module *cmod); + void (*module_unload)(struct codetag_type *cttype, + struct codetag_module *cmod); }; struct codetag_iterator { @@ -65,4 +69,12 @@ void codetag_to_text(struct seq_buf *out, struct codetag *ct); struct codetag_type * codetag_register_type(const struct codetag_type_desc *desc); +#if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) +void codetag_load_module(struct module *mod); +void codetag_unload_module(struct module *mod); +#else +static inline void codetag_load_module(struct module *mod) {} +static inline void codetag_unload_module(struct module *mod) {} +#endif + #endif /* _LINUX_CODETAG_H */ diff --git a/kernel/module/main.c b/kernel/module/main.c index e1e8a7a9d6c1..ffa6b3e9cb43 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -56,6 +56,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -1242,6 +1243,7 @@ static void free_module(struct module *mod) { trace_module_free(mod); + codetag_unload_module(mod); mod_sysfs_teardown(mod); /* @@ -2995,6 +2997,8 @@ static int load_module(struct load_info *info, const char __user *uargs, /* Get rid of temporary copy. */ free_copy(info, flags); + codetag_load_module(mod); + /* Done! */ trace_module_load(mod); diff --git a/lib/codetag.c b/lib/codetag.c index 8b5b89ad508d..54d2828eba25 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -124,15 +124,20 @@ static void *get_symbol(struct module *mod, const char *prefix, const char *name { DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN); const char *buf; + void *ret; seq_buf_printf(&sb, "%s%s", prefix, name); if (seq_buf_has_overflowed(&sb)) return NULL; buf = seq_buf_str(&sb); - return mod ? + preempt_disable(); + ret = mod ? (void *)find_kallsyms_symbol_value(mod, buf) : (void *)kallsyms_lookup_name(buf); + preempt_enable(); + + return ret; } static struct codetag_range get_section_range(struct module *mod, @@ -173,8 +178,11 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) down_write(&cttype->mod_lock); err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL); - if (err >= 0) + if (err >= 0) { cttype->count += range_size(cttype, &range); + if (cttype->desc.module_load) + cttype->desc.module_load(cttype, cmod); + } up_write(&cttype->mod_lock); if (err < 0) { @@ -185,6 +193,52 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) return 0; } +void codetag_load_module(struct module *mod) +{ + struct codetag_type *cttype; + + if (!mod) + return; + + mutex_lock(&codetag_lock); + list_for_each_entry(cttype, &codetag_types, link) + codetag_module_init(cttype, mod); + mutex_unlock(&codetag_lock); +} + +void codetag_unload_module(struct module *mod) +{ + struct codetag_type *cttype; + + if (!mod) + return; + + mutex_lock(&codetag_lock); + list_for_each_entry(cttype, &codetag_types, link) { + struct codetag_module *found = NULL; + struct codetag_module *cmod; + unsigned long mod_id, tmp; + + down_write(&cttype->mod_lock); + idr_for_each_entry_ul(&cttype->mod_idr, cmod, tmp, mod_id) { + if (cmod->mod && cmod->mod == mod) { + found = cmod; + break; + } + } + if (found) { + if (cttype->desc.module_unload) + cttype->desc.module_unload(cttype, cmod); + + cttype->count -= range_size(cttype, &cmod->range); + idr_remove(&cttype->mod_idr, mod_id); + kfree(cmod); + } + up_write(&cttype->mod_lock); + } + mutex_unlock(&codetag_lock); +} + #else /* CONFIG_MODULES */ static int codetag_module_init(struct codetag_type *cttype, struct module *mod) { return 0; } #endif /* CONFIG_MODULES */ -- cgit v1.2.3 From 47a92dfbe01f41bcbf359250ccb3caa589763abf Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 21 Mar 2024 09:36:34 -0700 Subject: lib: prevent module unloading if memory is not freed MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Skip freeing module's data section if there are non-zero allocation tags because otherwise, once these allocations are freed, the access to their code tag would cause UAF. Link: https://lkml.kernel.org/r/20240321163705.3067592-13-surenb@google.com Signed-off-by: Suren Baghdasaryan Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Kent Overstreet Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton --- include/linux/codetag.h | 6 +++--- kernel/module/main.c | 27 +++++++++++++++++++-------- lib/codetag.c | 11 ++++++++--- 3 files changed, 30 insertions(+), 14 deletions(-) (limited to 'include/linux/codetag.h') diff --git a/include/linux/codetag.h b/include/linux/codetag.h index c44f5b83f24d..bfd0ba5c4185 100644 --- a/include/linux/codetag.h +++ b/include/linux/codetag.h @@ -35,7 +35,7 @@ struct codetag_type_desc { size_t tag_size; void (*module_load)(struct codetag_type *cttype, struct codetag_module *cmod); - void (*module_unload)(struct codetag_type *cttype, + bool (*module_unload)(struct codetag_type *cttype, struct codetag_module *cmod); }; @@ -71,10 +71,10 @@ codetag_register_type(const struct codetag_type_desc *desc); #if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) void codetag_load_module(struct module *mod); -void codetag_unload_module(struct module *mod); +bool codetag_unload_module(struct module *mod); #else static inline void codetag_load_module(struct module *mod) {} -static inline void codetag_unload_module(struct module *mod) {} +static inline bool codetag_unload_module(struct module *mod) { return true; } #endif #endif /* _LINUX_CODETAG_H */ diff --git a/kernel/module/main.c b/kernel/module/main.c index ffa6b3e9cb43..2d25eebc549d 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1211,15 +1211,19 @@ static void *module_memory_alloc(unsigned int size, enum mod_mem_type type) return module_alloc(size); } -static void module_memory_free(void *ptr, enum mod_mem_type type) +static void module_memory_free(void *ptr, enum mod_mem_type type, + bool unload_codetags) { + if (!unload_codetags && mod_mem_type_is_core_data(type)) + return; + if (mod_mem_use_vmalloc(type)) vfree(ptr); else module_memfree(ptr); } -static void free_mod_mem(struct module *mod) +static void free_mod_mem(struct module *mod, bool unload_codetags) { for_each_mod_mem_type(type) { struct module_memory *mod_mem = &mod->mem[type]; @@ -1230,20 +1234,27 @@ static void free_mod_mem(struct module *mod) /* Free lock-classes; relies on the preceding sync_rcu(). */ lockdep_free_key_range(mod_mem->base, mod_mem->size); if (mod_mem->size) - module_memory_free(mod_mem->base, type); + module_memory_free(mod_mem->base, type, + unload_codetags); } /* MOD_DATA hosts mod, so free it at last */ lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size); - module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA); + module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA, unload_codetags); } /* Free a module, remove from lists, etc. */ static void free_module(struct module *mod) { + bool unload_codetags; + trace_module_free(mod); - codetag_unload_module(mod); + unload_codetags = codetag_unload_module(mod); + if (!unload_codetags) + pr_warn("%s: memory allocation(s) from the module still alive, cannot unload cleanly\n", + mod->name); + mod_sysfs_teardown(mod); /* @@ -1285,7 +1296,7 @@ static void free_module(struct module *mod) kfree(mod->args); percpu_modfree(mod); - free_mod_mem(mod); + free_mod_mem(mod, unload_codetags); } void *__symbol_get(const char *symbol) @@ -2298,7 +2309,7 @@ static int move_module(struct module *mod, struct load_info *info) return 0; out_enomem: for (t--; t >= 0; t--) - module_memory_free(mod->mem[t].base, t); + module_memory_free(mod->mem[t].base, t, true); return ret; } @@ -2428,7 +2439,7 @@ static void module_deallocate(struct module *mod, struct load_info *info) percpu_modfree(mod); module_arch_freeing_init(mod); - free_mod_mem(mod); + free_mod_mem(mod, true); } int __weak module_finalize(const Elf_Ehdr *hdr, diff --git a/lib/codetag.c b/lib/codetag.c index 54d2828eba25..408062f722ce 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -5,6 +5,7 @@ #include #include #include +#include struct codetag_type { struct list_head link; @@ -206,12 +207,13 @@ void codetag_load_module(struct module *mod) mutex_unlock(&codetag_lock); } -void codetag_unload_module(struct module *mod) +bool codetag_unload_module(struct module *mod) { struct codetag_type *cttype; + bool unload_ok = true; if (!mod) - return; + return true; mutex_lock(&codetag_lock); list_for_each_entry(cttype, &codetag_types, link) { @@ -228,7 +230,8 @@ void codetag_unload_module(struct module *mod) } if (found) { if (cttype->desc.module_unload) - cttype->desc.module_unload(cttype, cmod); + if (!cttype->desc.module_unload(cttype, cmod)) + unload_ok = false; cttype->count -= range_size(cttype, &cmod->range); idr_remove(&cttype->mod_idr, mod_id); @@ -237,6 +240,8 @@ void codetag_unload_module(struct module *mod) up_write(&cttype->mod_lock); } mutex_unlock(&codetag_lock); + + return unload_ok; } #else /* CONFIG_MODULES */ -- cgit v1.2.3 From 1438d349d16b78d88f9e978a4a5496f078c8191b Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Thu, 21 Mar 2024 09:36:54 -0700 Subject: lib: add memory allocations report in show_mem() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Include allocations in show_mem reports. Link: https://lkml.kernel.org/r/20240321163705.3067592-33-surenb@google.com Signed-off-by: Kent Overstreet Signed-off-by: Suren Baghdasaryan Reviewed-by: Vlastimil Babka Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton --- include/linux/alloc_tag.h | 7 +++++++ include/linux/codetag.h | 1 + lib/alloc_tag.c | 38 ++++++++++++++++++++++++++++++++++++++ lib/codetag.c | 5 +++++ mm/show_mem.c | 26 ++++++++++++++++++++++++++ 5 files changed, 77 insertions(+) (limited to 'include/linux/codetag.h') diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 0567766e50bd..d18388c0e9e1 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -31,6 +31,13 @@ struct alloc_tag { #ifdef CONFIG_MEM_ALLOC_PROFILING +struct codetag_bytes { + struct codetag *ct; + s64 bytes; +}; + +size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sleep); + static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct) { return container_of(ct, struct alloc_tag, ct); diff --git a/include/linux/codetag.h b/include/linux/codetag.h index bfd0ba5c4185..c2a579ccd455 100644 --- a/include/linux/codetag.h +++ b/include/linux/codetag.h @@ -61,6 +61,7 @@ struct codetag_iterator { } void codetag_lock_module_list(struct codetag_type *cttype, bool lock); +bool codetag_trylock_module_list(struct codetag_type *cttype); struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype); struct codetag *codetag_next_ct(struct codetag_iterator *iter); diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 6bd8e85beaf7..26af9982ddc4 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -89,6 +89,44 @@ static const struct seq_operations allocinfo_seq_op = { .show = allocinfo_show, }; +size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sleep) +{ + struct codetag_iterator iter; + struct codetag *ct; + struct codetag_bytes n; + unsigned int i, nr = 0; + + if (can_sleep) + codetag_lock_module_list(alloc_tag_cttype, true); + else if (!codetag_trylock_module_list(alloc_tag_cttype)) + return 0; + + iter = codetag_get_ct_iter(alloc_tag_cttype); + while ((ct = codetag_next_ct(&iter))) { + struct alloc_tag_counters counter = alloc_tag_read(ct_to_alloc_tag(ct)); + + n.ct = ct; + n.bytes = counter.bytes; + + for (i = 0; i < nr; i++) + if (n.bytes > tags[i].bytes) + break; + + if (i < count) { + nr -= nr == count; + memmove(&tags[i + 1], + &tags[i], + sizeof(tags[0]) * (nr - i)); + nr++; + tags[i] = n; + } + } + + codetag_lock_module_list(alloc_tag_cttype, false); + + return nr; +} + static void __init procfs_init(void) { proc_create_seq("allocinfo", 0444, NULL, &allocinfo_seq_op); diff --git a/lib/codetag.c b/lib/codetag.c index 408062f722ce..5ace625f2328 100644 --- a/lib/codetag.c +++ b/lib/codetag.c @@ -36,6 +36,11 @@ void codetag_lock_module_list(struct codetag_type *cttype, bool lock) up_read(&cttype->mod_lock); } +bool codetag_trylock_module_list(struct codetag_type *cttype) +{ + return down_read_trylock(&cttype->mod_lock) != 0; +} + struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype) { struct codetag_iterator iter = { diff --git a/mm/show_mem.c b/mm/show_mem.c index 8dcfafbd283c..bdb439551eef 100644 --- a/mm/show_mem.c +++ b/mm/show_mem.c @@ -423,4 +423,30 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) #ifdef CONFIG_MEMORY_FAILURE printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages)); #endif +#ifdef CONFIG_MEM_ALLOC_PROFILING + { + struct codetag_bytes tags[10]; + size_t i, nr; + + nr = alloc_tag_top_users(tags, ARRAY_SIZE(tags), false); + if (nr) { + pr_notice("Memory allocations:\n"); + for (i = 0; i < nr; i++) { + struct codetag *ct = tags[i].ct; + struct alloc_tag *tag = ct_to_alloc_tag(ct); + struct alloc_tag_counters counter = alloc_tag_read(tag); + + /* Same as alloc_tag_to_text() but w/o intermediate buffer */ + if (ct->modname) + pr_notice("%12lli %8llu %s:%u [%s] func:%s\n", + counter.bytes, counter.calls, ct->filename, + ct->lineno, ct->modname, ct->function); + else + pr_notice("%12lli %8llu %s:%u func:%s\n", + counter.bytes, counter.calls, ct->filename, + ct->lineno, ct->function); + } + } + } +#endif } -- cgit v1.2.3