In fs/read_write.c:
SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
unsigned long, offset_low, loff_t __user *, result,
unsigned int, origin)
...
offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
origin);
On a 64-bit system that define CONFIG_HAVE_SYSCALL_WRAPPERS SYSCALL_DEFINEx
will truncate long arguments to 32-bit and on some architectures such as
MIPS sign-extended to 64-bit again. On such architectures passing a
value with bit 31 in offset_low set will result in a huge 64-bit offset
being passed to vfs_llseek() and it failiing with EINVAL.
The issue was discovered on Debian's MIPS infrastructure machines running
e2fsck:
[...]
This was noticed on one of the Debian
infrastructure machines where, after an upgrade, e2fsck began failing
with errors like:
Error reading block 524290 (Invalid argument) while getting next inode
from scan. Ignore error<y>?
[...]
Fixed by changing the prototype to use 32-bit arguments for the higher
and lower half of offset of sys_llseek.
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
fs/read_write.c | 4 ++--
include/linux/syscalls.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index 400fe81..2fb171e 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -171,8 +171,8 @@ bad:
}
#ifdef __ARCH_WANT_SYS_LLSEEK
-SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
- unsigned long, offset_low, loff_t __user *, result,
+SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
+ unsigned int, offset_low, loff_t __user *, result,
unsigned int, origin)
{
int retval;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index f9f900c..5c593d4 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -444,8 +444,8 @@ asmlinkage long sys_utimes(char __user *filename,
struct timeval __user *utimes);
asmlinkage long sys_lseek(unsigned int fd, off_t offset,
unsigned int origin);
-asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
- unsigned long offset_low, loff_t __user *result,
+asmlinkage long sys_llseek(unsigned int fd, unsigned int offset_high,
+ unsigned int offset_low, loff_t __user *result,
unsigned int origin);
asmlinkage long sys_read(unsigned int fd, char __user *buf, size_t count);
asmlinkage long sys_readahead(int fd, loff_t offset, size_t count);
