From: Dan Carpenter Date: Thu, 15 Jul 2010 00:56:37 +0000 (-0700) Subject: net/sched: potential data corruption X-Git-Tag: firefly_0821_release~9833^2~1306^2~225 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0eff683f737bf684dc9299e2eaca79cceb80a8c1;p=firefly-linux-kernel-4.4.55.git net/sched: potential data corruption The reset_policy() does: memset(d->tcfd_defdata, 0, SIMP_MAX_DATA); strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); In the original code, the size of d->tcfd_defdata wasn't fixed and if strlen(defdata) was less than 31, reset_policy() would cause memory corruption. Please Note: The original alloc_defdata() assumes defdata is 32 characters and a NUL terminator while reset_policy() assumes defdata is 31 characters and a NUL. This patch updates alloc_defdata() to match reset_policy() (ie a shorter string). I'm not very familiar with this code so please review carefully. Signed-off-by: Dan Carpenter Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c index 1b4bc691d7d1..4a1d640b0cf1 100644 --- a/net/sched/act_simple.c +++ b/net/sched/act_simple.c @@ -73,10 +73,10 @@ static int tcf_simp_release(struct tcf_defact *d, int bind) static int alloc_defdata(struct tcf_defact *d, char *defdata) { - d->tcfd_defdata = kstrndup(defdata, SIMP_MAX_DATA, GFP_KERNEL); + d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL); if (unlikely(!d->tcfd_defdata)) return -ENOMEM; - + strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); return 0; }