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fib_trie: Fix shift by 32 in fib_table_lookup

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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 <toralf.foerster@gmx.de>
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck 2016-01-28 13:42:24 -08:00 committed by David S. Miller
parent 59a557be38
commit a5829f536b
1 changed files with 4 additions and 3 deletions
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7
net/ipv4/fib_trie.c
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@ -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)