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[Qemu-devel] [PATCH v1 1/2] slirp: correct size computation while concat
From: |
P J P |
Subject: |
[Qemu-devel] [PATCH v1 1/2] slirp: correct size computation while concatenating mbuf |
Date: |
Wed, 6 Jun 2018 16:05:48 +0530 |
From: Prasad J Pandit <address@hidden>
While reassembling incoming fragmented datagrams, 'm_cat' routine
extends the 'mbuf' buffer, if it has insufficient room. It computes
a wrong buffer size, which leads to overwriting adjacent heap buffer
area. Correct this size computation in m_cat.
Reported-by: ZDI Disclosures <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
slirp/mbuf.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
Update v1: fixed indentation
https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg01121.html
diff --git a/slirp/mbuf.c b/slirp/mbuf.c
index 5ff24559fd..6650981fc7 100644
--- a/slirp/mbuf.c
+++ b/slirp/mbuf.c
@@ -137,8 +137,9 @@ m_cat(struct mbuf *m, struct mbuf *n)
/*
* If there's no room, realloc
*/
- if (M_FREEROOM(m) < n->m_len)
- m_inc(m,m->m_size+MINCSIZE);
+ if (M_FREEROOM(m) < n->m_len) {
+ m_inc(m, m->m_len + n->m_len);
+ }
memcpy(m->m_data+m->m_len, n->m_data, n->m_len);
m->m_len += n->m_len;
@@ -158,12 +159,12 @@ m_inc(struct mbuf *m, int size)
if (m->m_flags & M_EXT) {
datasize = m->m_data - m->m_ext;
- m->m_ext = g_realloc(m->m_ext, size);
+ m->m_ext = g_realloc(m->m_ext, size + datasize);
m->m_data = m->m_ext + datasize;
} else {
char *dat;
datasize = m->m_data - m->m_dat;
- dat = g_malloc(size);
+ dat = g_malloc(size + datasize);
memcpy(dat, m->m_dat, m->m_size);
m->m_ext = dat;
@@ -171,7 +172,7 @@ m_inc(struct mbuf *m, int size)
m->m_flags |= M_EXT;
}
- m->m_size = size;
+ m->m_size = size + datasize;
}
--
2.17.1