From: Samuel Thibault <samuel.thiba...@ens-lyon.org>
When the first fragment does not fit in the preallocated buffer, q will
already be pointing to the ext buffer, so we mustn't try to update it.
Signed-off-by: Samuel Thibault <samuel.thiba...@ens-lyon.org>
(cherry picked from libslirp commit 126c04acbabd7ad32c2b018fe10dfac2a3bc1210)
Fixes: CVE-2019-14378
Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
slirp/ip_input.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/slirp/ip_input.c b/slirp/ip_input.c
index 348e1dca5a..07d8808671 100644
--- a/slirp/ip_input.c
+++ b/slirp/ip_input.c
@@ -334,6 +334,8 @@ insert:
q = fp->frag_link.next;
m = dtom(slirp, q);
+ int was_ext = m->m_flags & M_EXT;
+
q = (struct ipasfrag *) q->ipf_next;
while (q != (struct ipasfrag*)&fp->frag_link) {
struct mbuf *t = dtom(slirp, q);
@@ -356,7 +358,7 @@ insert:
* the old buffer (in the mbuf), so we must point ip
* into the new buffer.
*/
- if (m->m_flags & M_EXT) {
+ if (!was_ext && m->m_flags & M_EXT) {
int delta = (char *)q - m->m_dat;
q = (struct ipasfrag *)(m->m_ext + delta);
}
--
2.20.1
