[PATCH 1/3] fs: fix archiecture-specific compat_ftruncate64
Jan Kara
jack at suse.cz
Mon Mar 23 21:27:06 AEDT 2026
On Mon 23-03-26 08:01:44, Christoph Hellwig wrote:
> The "small" argument to do_sys_ftruncate indicates if > 32-bit size
> should be reject, but all the arch-specific compat ftruncate64
> implementations get this wrong. Merge do_sys_ftruncate and
> ksys_ftruncate, replace the integer as boolean small flag with a
> descriptive one about LFS semantics, and use it correctly in the
> architecture-specific ftruncate64 implementations.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Fixes: 3dd681d944f6 ("arm64: 32-bit (compat) applications support")
> Signed-off-by: Christoph Hellwig <hch at lst.de>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack at suse.cz>
Honza
> ---
> arch/arm64/kernel/sys32.c | 2 +-
> arch/mips/kernel/linux32.c | 2 +-
> arch/parisc/kernel/sys_parisc.c | 4 ++--
> arch/powerpc/kernel/sys_ppc32.c | 2 +-
> arch/sparc/kernel/sys_sparc32.c | 2 +-
> arch/x86/kernel/sys_ia32.c | 3 ++-
> fs/internal.h | 1 -
> fs/open.c | 12 ++++++------
> include/linux/syscalls.h | 8 ++------
> 9 files changed, 16 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c
> index 96bcfb907443..12a948f3a504 100644
> --- a/arch/arm64/kernel/sys32.c
> +++ b/arch/arm64/kernel/sys32.c
> @@ -89,7 +89,7 @@ COMPAT_SYSCALL_DEFINE4(aarch32_truncate64, const char __user *, pathname,
> COMPAT_SYSCALL_DEFINE4(aarch32_ftruncate64, unsigned int, fd, u32, __pad,
> arg_u32p(length))
> {
> - return ksys_ftruncate(fd, arg_u64(length));
> + return ksys_ftruncate(fd, arg_u64(length), FTRUNCATE_LFS);
> }
>
> COMPAT_SYSCALL_DEFINE5(aarch32_readahead, int, fd, u32, __pad,
> diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
> index a0c0a7a654e9..fe9a787db569 100644
> --- a/arch/mips/kernel/linux32.c
> +++ b/arch/mips/kernel/linux32.c
> @@ -60,7 +60,7 @@ SYSCALL_DEFINE4(32_truncate64, const char __user *, path,
> SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,
> unsigned long, a2, unsigned long, a3)
> {
> - return ksys_ftruncate(fd, merge_64(a2, a3));
> + return ksys_ftruncate(fd, merge_64(a2, a3), FTRUNCATE_LFS);
> }
>
> SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high,
> diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
> index b2cdbb8a12b1..fcb0d8069139 100644
> --- a/arch/parisc/kernel/sys_parisc.c
> +++ b/arch/parisc/kernel/sys_parisc.c
> @@ -216,7 +216,7 @@ asmlinkage long parisc_truncate64(const char __user * path,
> asmlinkage long parisc_ftruncate64(unsigned int fd,
> unsigned int high, unsigned int low)
> {
> - return ksys_ftruncate(fd, (long)high << 32 | low);
> + return ksys_ftruncate(fd, (long)high << 32 | low, FTRUNCATE_LFS);
> }
>
> /* stubs for the benefit of the syscall_table since truncate64 and truncate
> @@ -227,7 +227,7 @@ asmlinkage long sys_truncate64(const char __user * path, unsigned long length)
> }
> asmlinkage long sys_ftruncate64(unsigned int fd, unsigned long length)
> {
> - return ksys_ftruncate(fd, length);
> + return ksys_ftruncate(fd, length, FTRUNCATE_LFS);
> }
> asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
> {
> diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
> index d451a8229223..03fa487f2614 100644
> --- a/arch/powerpc/kernel/sys_ppc32.c
> +++ b/arch/powerpc/kernel/sys_ppc32.c
> @@ -101,7 +101,7 @@ PPC32_SYSCALL_DEFINE4(ppc_ftruncate64,
> unsigned int, fd, u32, reg4,
> unsigned long, len1, unsigned long, len2)
> {
> - return ksys_ftruncate(fd, merge_64(len1, len2));
> + return ksys_ftruncate(fd, merge_64(len1, len2), FTRUNCATE_LFS);
> }
>
> PPC32_SYSCALL_DEFINE6(ppc32_fadvise64,
> diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
> index f84a02ab6bf9..04432b82b9e3 100644
> --- a/arch/sparc/kernel/sys_sparc32.c
> +++ b/arch/sparc/kernel/sys_sparc32.c
> @@ -58,7 +58,7 @@ COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, path, u32, high, u32, lo
>
> COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd, u32, high, u32, low)
> {
> - return ksys_ftruncate(fd, ((u64)high << 32) | low);
> + return ksys_ftruncate(fd, ((u64)high << 32) | low, FTRUNCATE_LFS);
> }
>
> static int cp_compat_stat64(struct kstat *stat,
> diff --git a/arch/x86/kernel/sys_ia32.c b/arch/x86/kernel/sys_ia32.c
> index 6cf65397d225..610a1c2f4519 100644
> --- a/arch/x86/kernel/sys_ia32.c
> +++ b/arch/x86/kernel/sys_ia32.c
> @@ -61,7 +61,8 @@ SYSCALL_DEFINE3(ia32_truncate64, const char __user *, filename,
> SYSCALL_DEFINE3(ia32_ftruncate64, unsigned int, fd,
> unsigned long, offset_low, unsigned long, offset_high)
> {
> - return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
> + return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low,
> + FTRUNCATE_LFS);
> }
>
> /* warning: next two assume little endian */
> diff --git a/fs/internal.h b/fs/internal.h
> index cbc384a1aa09..2663823e273a 100644
> --- a/fs/internal.h
> +++ b/fs/internal.h
> @@ -199,7 +199,6 @@ extern int build_open_flags(const struct open_how *how, struct open_flags *op);
> struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
>
> int do_ftruncate(struct file *file, loff_t length, int small);
> -int do_sys_ftruncate(unsigned int fd, loff_t length, int small);
> int chmod_common(const struct path *path, umode_t mode);
> int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
> int flag);
> diff --git a/fs/open.c b/fs/open.c
> index 91f1139591ab..412d0d6fbaa7 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -197,7 +197,7 @@ int do_ftruncate(struct file *file, loff_t length, int small)
> ATTR_MTIME | ATTR_CTIME, file);
> }
>
> -int do_sys_ftruncate(unsigned int fd, loff_t length, int small)
> +int ksys_ftruncate(unsigned int fd, loff_t length, unsigned int flags)
> {
> if (length < 0)
> return -EINVAL;
> @@ -205,18 +205,18 @@ int do_sys_ftruncate(unsigned int fd, loff_t length, int small)
> if (fd_empty(f))
> return -EBADF;
>
> - return do_ftruncate(fd_file(f), length, small);
> + return do_ftruncate(fd_file(f), length, !(flags & FTRUNCATE_LFS));
> }
>
> SYSCALL_DEFINE2(ftruncate, unsigned int, fd, off_t, length)
> {
> - return do_sys_ftruncate(fd, length, 1);
> + return ksys_ftruncate(fd, length, 0);
> }
>
> #ifdef CONFIG_COMPAT
> COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_off_t, length)
> {
> - return do_sys_ftruncate(fd, length, 1);
> + return ksys_ftruncate(fd, length, 0);
> }
> #endif
>
> @@ -229,7 +229,7 @@ SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
>
> SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
> {
> - return do_sys_ftruncate(fd, length, 0);
> + return ksys_ftruncate(fd, length, FTRUNCATE_LFS);
> }
> #endif /* BITS_PER_LONG == 32 */
>
> @@ -245,7 +245,7 @@ COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
> COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd,
> compat_arg_u64_dual(length))
> {
> - return ksys_ftruncate(fd, compat_arg_u64_glue(length));
> + return ksys_ftruncate(fd, compat_arg_u64_glue(length), FTRUNCATE_LFS);
> }
> #endif
>
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 02bd6ddb6278..8787b3511c86 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1283,12 +1283,8 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
> AT_SYMLINK_NOFOLLOW);
> }
>
> -int do_sys_ftruncate(unsigned int fd, loff_t length, int small);
> -
> -static inline long ksys_ftruncate(unsigned int fd, loff_t length)
> -{
> - return do_sys_ftruncate(fd, length, 1);
> -}
> +#define FTRUNCATE_LFS (1u << 0) /* allow truncating > 32-bit */
> +int ksys_ftruncate(unsigned int fd, loff_t length, unsigned int flags);
>
> int do_sys_truncate(const char __user *pathname, loff_t length);
>
> --
> 2.47.3
>
--
Jan Kara <jack at suse.com>
SUSE Labs, CR
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