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From:   Gaosheng Cui <cuigaosheng1@huawei.com>
To:     <paul@paul-moore.com>, <eparis@redhat.com>
CC:     <linux-audit@redhat.com>, <linux-kernel@vger.kernel.org>,
        <xiujianfeng@huawei.com>, <wangweiyang2@huawei.com>
Subject: [PATCH -next,v2 1/2] audit: fix possible null-pointer dereference in audit_filter_rules
Date:   Wed, 13 Oct 2021 17:12:07 +0800
Message-ID: <20211013091208.36209-2-cuigaosheng1@huawei.com>
In-Reply-To: <20211013091208.36209-1-cuigaosheng1@huawei.com>
References: <20211013091208.36209-1-cuigaosheng1@huawei.com>
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Fix this possible null-pointer dereference in audit_filter_rules.

If ctx is null, a null-pointer dereference will occur:
    case AUDIT_SADDR_FAM:
        if (ctx->sockaddr)
		...
	break;

audit_filter_rules() error: we previously assumed 'ctx' could be null

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
---
 kernel/auditsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4ba3b8573ff4..42d4a4320526 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -647,7 +647,7 @@ static int audit_filter_rules(struct task_struct *tsk,
 			result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
 			break;
 		case AUDIT_SADDR_FAM:
-			if (ctx->sockaddr)
+			if (ctx && ctx->sockaddr)
 				result = audit_comparator(ctx->sockaddr->ss_family,
 							  f->op, f->val);
 			break;
-- 
2.30.0