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-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=468b732b6f76b138c0926eadf38ac88467dcd271;p=linux-beck.git rds: fix an integer overflow test in rds_info_getsockopt() "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 --- diff --git a/net/rds/info.c b/net/rds/info.c index 9a6b4f66187c..140a44a5f7b7 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; }