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| author | Marc-André Lureau <marcandre.lureau@redhat.com> | 2020-04-04 22:42:13 +0200 |
|---|---|---|
| committer | Marc-André Lureau <marcandre.lureau@redhat.com> | 2020-04-06 12:43:30 +0200 |
| commit | 9bd6c5913271eabcb7768a58197ed3301fe19f2d (patch) | |
| tree | b045efa2e1fe9705c6ff793cec7f43ba49f25c24 | |
| parent | b2dd09156a1ff5adb20c8ad73055284c6be786ff (diff) | |
| download | slirp-9bd6c5913271eabcb7768a58197ed3301fe19f2d.zip slirp-9bd6c5913271eabcb7768a58197ed3301fe19f2d.tar.gz slirp-9bd6c5913271eabcb7768a58197ed3301fe19f2d.tar.bz2 | |
Fix use-afte-free in ip_reass() (CVE-2020-1983)
The q pointer is updated when the mbuf data is moved from m_dat to
m_ext.
m_ext buffer may also be realloc()'ed and moved during m_cat():
q should also be updated in this case.
Reported-by: Aviv Sasson <asasson@paloaltonetworks.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
| -rw-r--r-- | src/ip_input.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/src/ip_input.c b/src/ip_input.c index aa514ae..89a01d4 100644 --- a/src/ip_input.c +++ b/src/ip_input.c @@ -327,8 +327,7 @@ insert: */ q = fp->frag_link.next; m = dtom(slirp, q); - - int was_ext = m->m_flags & M_EXT; + int delta = (char *)q - (m->m_flags & M_EXT ? m->m_ext : m->m_dat); q = (struct ipasfrag *)q->ipf_next; while (q != (struct ipasfrag *)&fp->frag_link) { @@ -351,8 +350,7 @@ insert: * then an m_ext buffer was alloced. But fp->ipq_next points to the old * buffer (in the mbuf), so we must point ip into the new buffer. */ - if (!was_ext && m->m_flags & M_EXT) { - int delta = (char *)q - m->m_dat; + if (m->m_flags & M_EXT) { q = (struct ipasfrag *)(m->m_ext + delta); } |