diff options
| author | Michael Roth <mdroth@linux.vnet.ibm.com> | 2019-09-24 16:04:04 -0500 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2019-10-01 19:14:07 -0500 |
| commit | b27192be13da3fb59f51185d9a1f944b3474b2fc (patch) | |
| tree | 75c7bec0a04f889ca41a47eb201a0507e6e869e7 | |
| parent | c2e03e2aa42d0f4f41deb08c2655503835840afa (diff) | |
slirp: ip_reass: Fix use after free
Using ip_deq after m_free might read pointers from an allocation reuse.
This would be difficult to exploit, but that is still related with
CVE-2019-14378 which generates fragmented IP packets that would trigger this
issue and at least produce a DoS.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(from libslirp.git commit c59279437eda91841b9d26079c70b8a540d41204)
Fixes: CVE-2019-15890
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | slirp/src/ip_input.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/slirp/src/ip_input.c b/slirp/src/ip_input.c index 68a99de5b5..89ae04e0c1 100644 --- a/slirp/src/ip_input.c +++ b/slirp/src/ip_input.c @@ -297,6 +297,7 @@ ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp) */ while (q != (struct ipasfrag*)&fp->frag_link && ip->ip_off + ip->ip_len > q->ipf_off) { + struct ipasfrag *prev; i = (ip->ip_off + ip->ip_len) - q->ipf_off; if (i < q->ipf_len) { q->ipf_len -= i; @@ -304,9 +305,10 @@ ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp) m_adj(dtom(slirp, q), i); break; } + prev = q; q = q->ipf_next; - m_free(dtom(slirp, q->ipf_prev)); - ip_deq(q->ipf_prev); + ip_deq(prev); + m_free(dtom(slirp, prev)); } insert: |