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authorAnton Kolesov <Anton.Kolesov@synopsys.com>2014-08-01 22:18:47 +0400
committerBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2014-08-18 12:01:36 +0200
commit361285886aa319a56c803f2fb783457f3e80f564 (patch)
treeac08937811c6701bb63951c10423146422193257 /libc/sysdeps
parent95ec1755ef61629169a79a616ec478988bb6ce7d (diff)
lseek: Correct order of offset arguments
There was a runtime error in systems without large file support. Call fseek(fd, 4096, SEEK_SET) has been failing with EINVAL, though it was succeeding for offset = 4092. This has been happening because llseek system call accepts 64-bit value as an offset argument and lseek function has been ordering 32-bits words that form this offset value, according to the endianness. However this ordering to match endianness is not required, because llseek doesn't accept one 64-bit offset argument, it accepts two 32-bit offset argument, then stitches them into one following its endianness. As a result on little endian system, order of words has been swapped two time: in libc and in kernel. Thus call to fseek with offset 4096 (0x1000) was doing a system call to llseek with offset 0x1000_0000_0000. I'm not entirely sure why then offset = 4092 hasn't been failing then. This patch removes malicious swap of words when calling llseek. Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com> Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Diffstat (limited to 'libc/sysdeps')
-rw-r--r--libc/sysdeps/linux/common/lseek.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/libc/sysdeps/linux/common/lseek.c b/libc/sysdeps/linux/common/lseek.c
index 500c6bf9d..11a1fbb3e 100644
--- a/libc/sysdeps/linux/common/lseek.c
+++ b/libc/sysdeps/linux/common/lseek.c
@@ -24,9 +24,7 @@ off_t __NC(lseek)(int fd, off_t offset, int whence)
#elif __WORDSIZE == 32
__off64_t result;
__off_t high = 0;
- return INLINE_SYSCALL(llseek, 5, fd,
- __LONG_LONG_PAIR(high, offset),
- &result, whence) ?: result;
+ return INLINE_SYSCALL(llseek, 5, fd, high, offset, &result, whence) ?: result;
#endif
/* No need to handle __WORDSIZE == 64 as such a kernel won't define __NR_llseek */
}