diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2016-08-11 18:59:39 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2016-08-16 16:42:03 +0100 |
| commit | 9fea273c8511dd6e34138d028db774b031c0f70c (patch) | |
| tree | 3d1950f07bfdb30eda3257cbbd7056ed52c51eb7 /linux-user | |
| parent | 9c37146782e7850877d452da47dc451ba73aa62d (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.c | 2 |
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 { |