File 0224-libslirp-tftp-check-tftp_input-buff.patch of Package qemu-linux-user.20748

From: Jose R Ziviani <jose.ziviani@suse.com>
Date: Thu, 8 Jul 2021 07:51:00 -0600
Subject: libslirp: tftp: check tftp_input buffer size
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Git-commit: 3f17948137155f025f7809fdc38576d5d2451c3d
References: bsc#1187366, CVE-2021-3595

Fixes: CVE-2021-3595
Fixes: https://gitlab.freedesktop.org/slirp/libslirp/-/issues/46

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jose R Ziviani <jose.ziviani@suse.com>
---
 slirp/tftp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/slirp/tftp.c b/slirp/tftp.c
index a9bc4bb1b65819f10cb5f3029b9c..f4ce9caaf9d8f9481ce60ca431f5 100644
--- a/slirp/tftp.c
+++ b/slirp/tftp.c
@@ -439,7 +439,11 @@ static void tftp_handle_error(Slirp *slirp, struct sockaddr_storage *srcsas,
 
 void tftp_input(struct sockaddr_storage *srcsas, struct mbuf *m)
 {
-  struct tftp_t *tp = (struct tftp_t *)m->m_data;
+  struct tftp_t *tp = mtod_check(m, offsetof(struct tftp_t, x.tp_buf));
+
+  if (tp == NULL) {
+    return;
+  }
 
   switch(ntohs(tp->tp_op)) {
   case TFTP_RRQ: