From: Dan Carpenter Date: Sat, 1 Aug 2015 12:33:26 +0000 (+0300) Subject: rds: fix an integer overflow test in rds_info_getsockopt() X-Git-Tag: v3.2.72~96 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f3a66bdc88c3261f55b942453476e623056b92d9;p=pandora-kernel.git rds: fix an integer overflow test in rds_info_getsockopt() commit 468b732b6f76b138c0926eadf38ac88467dcd271 upstream. "len" is a signed integer. We check that len is not negative, so it goes from zero to INT_MAX. PAGE_SIZE is unsigned long so the comparison is type promoted to unsigned long. ULONG_MAX - 4095 is a higher than INT_MAX so the condition can never be true. I don't know if this is harmful but it seems safe to limit "len" to INT_MAX - 4095. Fixes: a8c879a7ee98 ('RDS: Info and stats') Signed-off-by: Dan Carpenter Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- diff --git a/net/rds/info.c b/net/rds/info.c index f1c016c4146e..a4adb396880a 100644 --- a/net/rds/info.c +++ b/net/rds/info.c @@ -176,7 +176,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, /* check for all kinds of wrapping and the like */ start = (unsigned long)optval; - if (len < 0 || len + PAGE_SIZE - 1 < len || start + len < start) { + if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || start + len < start) { ret = -EINVAL; goto out; }