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| author | Arnd Bergmann <arnd@arndb.de> | 2024-06-19 12:34:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-05 10:31:59 +0300 |
| commit | 5ae6af68410bdad6181ec82104bb9985a7a6a0fa (patch) | |
| tree | c999b035508b04210874f208b46ca4af922ef150 | |
| parent | 702c1edbafb2e6f9d20f6d391273b5be09d366a5 (diff) | |
| download | linux-5ae6af68410bdad6181ec82104bb9985a7a6a0fa.tar.xz | |
ftruncate: pass a signed offset
commit 4b8e88e563b5f666446d002ad0dc1e6e8e7102b0 upstream.
The old ftruncate() syscall, using the 32-bit off_t misses a sign
extension when called in compat mode on 64-bit architectures. As a
result, passing a negative length accidentally succeeds in truncating
to file size between 2GiB and 4GiB.
Changing the type of the compat syscall to the signed compat_off_t
changes the behavior so it instead returns -EINVAL.
The native entry point, the truncate() syscall and the corresponding
loff_t based variants are all correct already and do not suffer
from this mistake.
Fixes: 3f6d078d4acc ("fix compat truncate/ftruncate")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/open.c | 4 | ||||
| -rw-r--r-- | include/linux/compat.h | 2 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 2 |
3 files changed, 4 insertions, 4 deletions
diff --git a/fs/open.c b/fs/open.c index 51dc46620d03..0d63c94e1c5e 100644 --- a/fs/open.c +++ b/fs/open.c @@ -199,13 +199,13 @@ out: return error; } -SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) +SYSCALL_DEFINE2(ftruncate, unsigned int, fd, off_t, length) { return do_sys_ftruncate(fd, length, 1); } #ifdef CONFIG_COMPAT -COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length) +COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_off_t, length) { return do_sys_ftruncate(fd, length, 1); } diff --git a/include/linux/compat.h b/include/linux/compat.h index 594357881b0b..77e84d17521e 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -621,7 +621,7 @@ asmlinkage long compat_sys_fstatfs(unsigned int fd, asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user *buf); asmlinkage long compat_sys_truncate(const char __user *, compat_off_t); -asmlinkage long compat_sys_ftruncate(unsigned int, compat_ulong_t); +asmlinkage long compat_sys_ftruncate(unsigned int, compat_off_t); /* No generic prototype for truncate64, ftruncate64, fallocate */ asmlinkage long compat_sys_openat(int dfd, const char __user *filename, int flags, umode_t mode); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 27a6ba1c0ec4..ea36e53e3125 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -450,7 +450,7 @@ asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user *buf); asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf); asmlinkage long sys_truncate(const char __user *path, long length); -asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length); +asmlinkage long sys_ftruncate(unsigned int fd, off_t length); #if BITS_PER_LONG == 32 asmlinkage long sys_truncate64(const char __user *path, loff_t length); asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length); |