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authorPeter Maydell <peter.maydell@linaro.org>2016-08-11 18:59:39 +0100
committerPeter Maydell <peter.maydell@linaro.org>2016-08-16 16:42:03 +0100
commit9fea273c8511dd6e34138d028db774b031c0f70c (patch)
tree3d1950f07bfdb30eda3257cbbd7056ed52c51eb7 /linux-user
parent9c37146782e7850877d452da47dc451ba73aa62d (diff)
linux-user: Fix llseek with high bit of offset_low set
The llseek syscall takes two 32-bit arguments, offset_high and offset_low, which must be combined to form a single 64-bit offset. Unfortunately we were combining them with (uint64_t)arg2 << 32) | arg3 and arg3 is a signed type; this meant that when promoting arg3 to a 64-bit type it would be sign-extended. The effect was that if the offset happened to have bit 31 set then this bit would get sign-extended into all of bits 63..32. Explicitly cast arg3 to abi_ulong to avoid the erroneous sign extension. Reported-by: Chanho Park <parkch98@gmail.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Chanho Park <parkch98@gmail.com> Message-id: 1470938379-1133-1-git-send-email-peter.maydell@linaro.org
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/syscall.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 7edfe4a228..9facf7c345 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9389,7 +9389,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
{
int64_t res;
#if !defined(__NR_llseek)
- res = lseek(arg1, ((uint64_t)arg2 << 32) | arg3, arg5);
+ res = lseek(arg1, ((uint64_t)arg2 << 32) | (abi_ulong)arg3, arg5);
if (res == -1) {
ret = get_errno(res);
} else {