[Qemu-devel] [PATCH] linux-user: return EINVAL from prctl(PR_*_SECCOMP)

[James Cowgill <james.cowgill@mips.com>]

If an application tries to install a seccomp filter using
prctl(PR_SET_SECCOMP), the filter is likely for the target instead of the host
architecture. This will probably cause qemu to be immediately killed when it
executes another syscall.

Prevent this from happening by returning EINVAL from both seccomp prctl
calls. This is the error returned by the kernel when seccomp support is
disabled.

Fixes: https://bugs.launchpad.net/qemu/+bug/1726394
Signed-off-by: James Cowgill <james.cowgill@mips.com>
---
 linux-user/syscall.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d4497dec5d..43cd5fb2bb 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -10482,6 +10482,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             break;
         }
 #endif
+        case PR_GET_SECCOMP:
+        case PR_SET_SECCOMP:
+            ret = -TARGET_EINVAL;
+            break;
         default:
             /* Most prctl options have no pointer arguments */
             ret = get_errno(prctl(arg1, arg2, arg3, arg4, arg5));
-- 
2.15.0