diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-06-24 03:07:20 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-24 12:42:57 -0700 |
| commit | 624085a31c1ad6a80b1e53f686bf6ee92abbf6e8 (patch) | |
| tree | b03f714aab2751866be7f7eac9e853a284a559ca /net/ipv6 | |
| parent | d9b6d26f6569d3ff748f6ba7a9ea3929abe5a17e (diff) | |
ipv6: fix out-of-bound access in ip6_parse_tlv()
First problem is that optlen is fetched without checking
there is more than one byte to parse.
Fix this by taking care of IPV6_TLV_PAD1 before
fetching optlen (under appropriate sanity checks against len)
Second problem is that IPV6_TLV_PADN checks of zero
padding are performed before the check of remaining length.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: c1412fce7ecc ("net/ipv6/exthdrs.c: Strict PadN option checking")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/exthdrs.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c index 6f7da8f3e2e5..26882e165c9e 100644 --- a/net/ipv6/exthdrs.c +++ b/net/ipv6/exthdrs.c @@ -135,18 +135,23 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, len -= 2; while (len > 0) { - int optlen = nh[off + 1] + 2; - int i; + int optlen, i; - switch (nh[off]) { - case IPV6_TLV_PAD1: - optlen = 1; + if (nh[off] == IPV6_TLV_PAD1) { padlen++; if (padlen > 7) goto bad; - break; + off++; + len--; + continue; + } + if (len < 2) + goto bad; + optlen = nh[off + 1] + 2; + if (optlen > len) + goto bad; - case IPV6_TLV_PADN: + if (nh[off] == IPV6_TLV_PADN) { /* RFC 2460 states that the purpose of PadN is * to align the containing header to multiples * of 8. 7 is therefore the highest valid value. @@ -163,12 +168,7 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, if (nh[off + i] != 0) goto bad; } - break; - - default: /* Other TLV code so scan list */ - if (optlen > len) - goto bad; - + } else { tlv_count++; if (tlv_count > max_count) goto bad; @@ -188,7 +188,6 @@ static bool ip6_parse_tlv(const struct tlvtype_proc *procs, return false; padlen = 0; - break; } off += optlen; len -= optlen; |