| Message ID | 20210624100720.2310271-1-eric.dumazet@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 624085a31c1ad6a80b1e53f686bf6ee92abbf6e8 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2,net] ipv6: fix out-of-bound access in ip6_parse_tlv() | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | fail | 1 blamed authors not CCed: eldad@fogrefinery.com; 3 maintainers not CCed: yoshfuji@linux-ipv6.org eldad@fogrefinery.com dsahern@kernel.org |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 50 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
On Thu, 2021-06-24 at 03:07 -0700, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > 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> > --- > v2: Removed not needed optlen assignment for IPV6_TLV_PAD1 handling, > added the Fixes: tag for first problem, feedback from Paolo, thanks ! > > net/ipv6/exthdrs.c | 27 +++++++++++++-------------- > 1 file changed, 13 insertions(+), 14 deletions(-) > > diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c > index 6f7da8f3e2e5849f917853984c69bf02a0f1e27c..26882e165c9e37a105f988020031f03d6b1a5cf9 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; LGTM! Reviewd-by: Paolo Abeni <pabeni@redhat.com>
Hello: This patch was applied to netdev/net.git (refs/heads/master): On Thu, 24 Jun 2021 03:07:20 -0700 you wrote: > From: Eric Dumazet <edumazet@google.com> > > 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) > > [...] Here is the summary with links: - [v2,net] ipv6: fix out-of-bound access in ip6_parse_tlv() https://git.kernel.org/netdev/net/c/624085a31c1a You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c index 6f7da8f3e2e5849f917853984c69bf02a0f1e27c..26882e165c9e37a105f988020031f03d6b1a5cf9 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;