ppp: backport fix for CVE-2022-4603

(From OE-Core rev: d5d787b44b102e3a69e28948326e39f83fc1d98d)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 49 insertions, 0 deletions

diff --git a/meta/recipes-connectivity/ppp/ppp/CVE-2022-4603.patch b/meta/recipes-connectivity/ppp/ppp/CVE-2022-4603.patch
new file mode 100644
index 0000000000..4325b1d6b0
--- /dev/null
+++ b/meta/recipes-connectivity/ppp/ppp/CVE-2022-4603.patch
@@ -0,0 +1,48 @@
+From a75fb7b198eed50d769c80c36629f38346882cbf Mon Sep 17 00:00:00 2001
+From: Paul Mackerras <paulus@ozlabs.org>
+Date: Thu, 4 Aug 2022 12:23:08 +1000
+Subject: [PATCH] pppdump: Avoid out-of-range access to packet buffer
+
+This fixes a potential vulnerability where data is written to spkt.buf
+and rpkt.buf without a check on the array index.  To fix this, we
+check the array index (pkt->cnt) before storing the byte or
+incrementing the count.  This also means we no longer have a potential
+signed integer overflow on the increment of pkt->cnt.
+
+Fortunately, pppdump is not used in the normal process of setting up a
+PPP connection, is not installed setuid-root, and is not invoked
+automatically in any scenario that I am aware of.
+
+Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
+
+Upstream-Status: Backport
+Signed-off-by: Ross Burton <ross.burton@arm.com>
+---
+ pppdump/pppdump.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/pppdump/pppdump.c b/pppdump/pppdump.c
+index 2b815fc9..b85a8627 100644
+--- a/pppdump/pppdump.c
++++ b/pppdump/pppdump.c
+@@ -297,6 +297,10 @@ dumpppp(f)
+                            printf("%s aborted packet:\n     ", dir);
+                            q = "    ";
+                        }
++                       if (pkt->cnt >= sizeof(pkt->buf)) {
++                           printf("%s over-long packet truncated:\n     ", dir);
++                           q = "    ";
++                       }
+                        nb = pkt->cnt;
+                        p = pkt->buf;
+                        pkt->cnt = 0;
+@@ -400,7 +404,8 @@ dumpppp(f)
+                        c ^= 0x20;
+                        pkt->esc = 0;
+                    }
+-                   pkt->buf[pkt->cnt++] = c;
++                   if (pkt->cnt < sizeof(pkt->buf))
++                       pkt->buf[pkt->cnt++] = c;
+                    break;
+                }
+            }
diff --git a/meta/recipes-connectivity/ppp/ppp_2.4.9.bb b/meta/recipes-connectivity/ppp/ppp_2.4.9.bb
index 700ece61dc..7e3ae43b58 100644
--- a/meta/recipes-connectivity/ppp/ppp_2.4.9.bb
+++ b/meta/recipes-connectivity/ppp/ppp_2.4.9.bb
@@ -25,6 +25,7 @@ SRC_URI = "https://download.samba.org/pub/${BPN}/${BP}.tar.gz \
            file://provider \
            file://ppp@.service \
            file://0001-ppp-fix-build-against-5.15-headers.patch \
+           file://CVE-2022-4603.patch \
            "
 
 SRC_URI[sha256sum] = "f938b35eccde533ea800b15a7445b2f1137da7f88e32a16898d02dee8adc058d"