[PATCH v2] audit: do a quick exit when syscall number is less than 0

From: Yang Yang <yang.yang29(a)zte.com.cn&gt; Userspace may use syscall with syscall number less than 0 by calling syscall(syscall_num,..). This kind of syscall could never be audited, because auditctl requires rule with syscall number >=0. Therefore we better do a quick handle no need to gohead with this situation. Note that auditctl may set rules auditing invalid syscall with syscall number bigger than NR_syscalls, to keep this mechanism working, we do no more check(context->major bigger than NR_syscalls or not). Signed-off-by: Yang Yang <yang.yang29(a)zte.com.cn&gt; Reported-by: Zeal Robot <zealci(a)zte.com.cn&gt; --- v2: - cancel checking against NR_syscalls --- kernel/auditsc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index ea2ee1181921..79118c811853 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2077,7 +2077,8 @@ void __audit_syscall_exit(int success, long return_code) struct audit_context *context = audit_context(); if (!context || context->dummy || - context->context != AUDIT_CTX_SYSCALL) + context->context != AUDIT_CTX_SYSCALL || + unlikely(context->major < 0)) goto out; /* this may generate CONFIG_CHANGE records */ -- 2.25.1