From a1b5bcffe4a4e6740545fe8ab4a3381da148ce89 Mon Sep 17 00:00:00 2001 From: Yi Wang Date: Wed, 25 Jul 2018 10:26:19 +0800 Subject: [PATCH] audit: fix potential null dereference 'context->module.name' commit b305f7ed0f4f494ad6f3ef5667501535d5a8fa31 upstream. The variable 'context->module.name' may be null pointer when kmalloc return null, so it's better to check it before using to avoid null dereference. Another one more thing this patch does is using kstrdup instead of (kmalloc + strcpy), and signal a lost record via audit_log_lost. Cc: stable@vger.kernel.org # 4.11 Signed-off-by: Yi Wang Reviewed-by: Jiang Biao Reviewed-by: Richard Guy Briggs Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman --- kernel/auditsc.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 677053a2fb57..76d789d6cea0 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -1274,8 +1274,12 @@ static void show_special(struct audit_context *context, int *call_panic) break; case AUDIT_KERN_MODULE: audit_log_format(ab, "name="); - audit_log_untrustedstring(ab, context->module.name); - kfree(context->module.name); + if (context->module.name) { + audit_log_untrustedstring(ab, context->module.name); + kfree(context->module.name); + } else + audit_log_format(ab, "(null)"); + break; } audit_log_end(ab); @@ -2387,8 +2391,9 @@ void __audit_log_kern_module(char *name) { struct audit_context *context = current->audit_context; - context->module.name = kmalloc(strlen(name) + 1, GFP_KERNEL); - strcpy(context->module.name, name); + context->module.name = kstrdup(name, GFP_KERNEL); + if (!context->module.name) + audit_log_lost("out of memory in __audit_log_kern_module"); context->type = AUDIT_KERN_MODULE; } -- 2.20.1