diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2024-06-19 11:34:09 +0200 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2024-06-24 18:29:20 +0200 |
| commit | 4b8e88e563b5f666446d002ad0dc1e6e8e7102b0 (patch) | |
| tree | 4a3b1870dc71d4f2d867bf0217465c451f40c2a3 | |
| parent | f2661062f16b2de5d7b6a5c42a9a5c96326b8454 (diff) | |
ftruncate: pass a signed offset
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>
| -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 89cafb572061..50e45bc7c4d8 100644 --- a/fs/open.c +++ b/fs/open.c @@ -202,13 +202,13 @@ long do_sys_ftruncate(unsigned int fd, loff_t length, int small) 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 233f61ec8afc..56cebaff0c91 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -608,7 +608,7 @@ 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 9104952d323d..ba9337709878 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -418,7 +418,7 @@ asmlinkage long sys_listmount(const struct mnt_id_req __user *req, u64 __user *mnt_ids, size_t nr_mnt_ids, unsigned int flags); 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); |