diff options
| author | Laurent Vivier <laurent@vivier.eu> | 2020-07-09 21:22:17 +0200 |
|---|---|---|
| committer | Laurent Vivier <laurent@vivier.eu> | 2020-07-13 21:22:08 +0200 |
| commit | 4c1850c130a31e6f3cc896a5ba5fb7a602540bc9 (patch) | |
| tree | fa01a74ef0e3107e4ba378757689baff3bddc969 /linux-user/strace.c | |
| parent | d8c08b1e6c7b1a5be1ec70e339437823a41b1946 (diff) | |
linux-user: Fix Coverity CID 1430271 / CID 1430272
In new functions print_ioctl() and print_syscall_ret_ioctl(), we don't
check if lock_user() returns NULL and this would cause a segfault in
thunk_print().
If lock_user() returns NULL don't call thunk_print() but prints only the
value of the (invalid) pointer.
Tested with:
# cat ioctl.c
#include <unistd.h>
#include <sys/ioctl.h>
int main(void)
{
int ret;
ret = ioctl(STDOUT_FILENO, TCGETS, 0xdeadbeef);
ret = ioctl(STDOUT_FILENO, TCSETSF, 0xdeadbeef);
return 0;
}
# QEMU_STRACE= ./ioctl
...
578 ioctl(1,TCGETS,0xdeadbeef) = -1 errno=2 (Bad address)
578 ioctl(1,TCSETSF,0xdeadbeef) = -1 errno=2 (Bad address)
...
# QEMU_STRACE= passwd
...
623 ioctl(0,TCGETS,0x3fffed04) = 0 ({})
623 ioctl(0,TCSETSF,{}) = 0
...
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Fixes: 79482e5987c8 ("linux-user: Add strace support for printing arguments of ioctl()")
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'linux-user/strace.c')
| -rw-r--r-- | linux-user/strace.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/linux-user/strace.c b/linux-user/strace.c index 5235b2260c..39554d9039 100644 --- a/linux-user/strace.c +++ b/linux-user/strace.c @@ -889,8 +889,12 @@ print_syscall_ret_ioctl(const struct syscallname *name, abi_long ret, arg_type++; target_size = thunk_type_size(arg_type, 0); argptr = lock_user(VERIFY_READ, arg2, target_size, 1); - thunk_print(argptr, arg_type); - unlock_user(argptr, arg2, target_size); + if (argptr) { + thunk_print(argptr, arg_type); + unlock_user(argptr, arg2, target_size); + } else { + print_pointer(arg2, 1); + } qemu_log(")"); } } @@ -3119,8 +3123,12 @@ print_ioctl(const struct syscallname *name, arg_type++; target_size = thunk_type_size(arg_type, 0); argptr = lock_user(VERIFY_READ, arg2, target_size, 1); - thunk_print(argptr, arg_type); - unlock_user(argptr, arg2, target_size); + if (argptr) { + thunk_print(argptr, arg_type); + unlock_user(argptr, arg2, target_size); + } else { + print_pointer(arg2, 1); + } break; } break; |