From a5829f536b3d11a57617e83d4bcb2b7d70671e98 Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Thu, 28 Jan 2016 13:42:24 -0800 Subject: [PATCH] fib_trie: Fix shift by 32 in fib_table_lookup MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The fib_table_lookup function had a shift by 32 that triggered a UBSAN warning. This was due to the fact that I had placed the shift first and then followed it with the check for the suffix length to ignore the undefined behavior. If we reorder this so that we verify the suffix is less than 32 before shifting the value we can avoid the issue. Reported-by: Toralf Förster Signed-off-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv4/fib_trie.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 744e5936c10d..22e73171ea63 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -1396,9 +1396,10 @@ found: struct fib_info *fi = fa->fa_info; int nhsel, err; - if ((index >= (1ul << fa->fa_slen)) && - ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen != KEYLENGTH))) - continue; + if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) { + if (index >= (1ul << fa->fa_slen)) + continue; + } if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos) continue; if (fi->fib_dead) -- 2.20.1