connman: fix CVE-2021-33833

ConnMan (aka Connection Manager) 1.30 through 1.39 has a stack-based
buffer overflow in uncompress in dnsproxy.c via NAME, RDATA, or
RDLENGTH (for A or AAAA).

Backport patch from:
https://git.kernel.org/pub/scm/network/connman/connman.git/commit/?id=eceb2e8d2341c041df55a5e2f047d9a8c491463c

CVE: CVE-2021-33833

(From OE-Core rev: 8eb4fdd19fe4b275c26c49120b364cd24ec151d5)

Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 73 insertions, 0 deletions

diff --git a/meta/recipes-connectivity/connman/connman/CVE-2021-33833.patch b/meta/recipes-connectivity/connman/connman/CVE-2021-33833.patch
new file mode 100644
index 0000000000..770948fb69
--- /dev/null
+++ b/meta/recipes-connectivity/connman/connman/CVE-2021-33833.patch
@@ -0,0 +1,72 @@
+From eceb2e8d2341c041df55a5e2f047d9a8c491463c Mon Sep 17 00:00:00 2001
+From: Valery Kashcheev <v.kascheev@omp.ru>
+Date: Mon, 7 Jun 2021 18:58:24 +0200
+Subject: dnsproxy: Check the length of buffers before memcpy
+
+Fix using a stack-based buffer overflow attack by checking the length of
+the ptr and uptr buffers.
+
+Fix debug message output.
+
+Fixes: CVE-2021-33833
+
+Upstream-Status: Backport
+https://git.kernel.org/pub/scm/network/connman/connman.git/commit/?id=eceb2e8d2341c041df55a5e2f047d9a8c491463c
+CVE: CVE-2021-33833
+Signed-off-by: Steve Sakoman <steve@sakoman.com>
+
+---
+ src/dnsproxy.c | 20 +++++++++++---------
+ 1 file changed, 11 insertions(+), 9 deletions(-)
+
+diff --git a/src/dnsproxy.c b/src/dnsproxy.c
+index de52df5a..38dbdd71 100644
+--- a/src/dnsproxy.c
++++ b/src/dnsproxy.c
+@@ -1788,17 +1788,15 @@ static char *uncompress(int16_t field_count, char *start, char *end,
+                 * tmp buffer.
+                 */
+ 
+-               debug("pos %d ulen %d left %d name %s", pos, ulen,
+-                       (int)(uncomp_len - (uptr - uncompressed)), uptr);
+-
+-               ulen = strlen(name);
+-               if ((uptr + ulen + 1) > uncomp_end) {
++               ulen = strlen(name) + 1;
++               if ((uptr + ulen) > uncomp_end)
+                        goto out;
+-               }
+-               strncpy(uptr, name, uncomp_len - (uptr - uncompressed));
++               strncpy(uptr, name, ulen);
++
++               debug("pos %d ulen %d left %d name %s", pos, ulen,
++                       (int)(uncomp_end - (uptr + ulen)), uptr);
+ 
+                uptr += ulen;
+-               *uptr++ = '\0';
+ 
+                ptr += pos;
+ 
+@@ -1841,7 +1839,7 @@ static char *uncompress(int16_t field_count, char *start, char *end,
+                } else if (dns_type == ns_t_a || dns_type == ns_t_aaaa) {
+                        dlen = uptr[-2] << 8 | uptr[-1];
+ 
+-                       if (ptr + dlen > end) {
++                       if ((ptr + dlen) > end || (uptr + dlen) > uncomp_end) {
+                                debug("data len %d too long", dlen);
+                                goto out;
+                        }
+@@ -1880,6 +1878,10 @@ static char *uncompress(int16_t field_count, char *start, char *end,
+                         * refresh interval, retry interval, expiration
+                         * limit and minimum ttl). They are 20 bytes long.
+                         */
++                       if ((uptr + 20) > uncomp_end || (ptr + 20) > end) {
++                               debug("soa record too long");
++                               goto out;
++                       }
+                        memcpy(uptr, ptr, 20);
+                        uptr += 20;
+                        ptr += 20;
+-- 
+cgit 1.2.3-1.el7
+
diff --git a/meta/recipes-connectivity/connman/connman_1.37.bb b/meta/recipes-connectivity/connman/connman_1.37.bb
index 096981364f..bdd1e590ec 100644
--- a/meta/recipes-connectivity/connman/connman_1.37.bb
+++ b/meta/recipes-connectivity/connman/connman_1.37.bb
@@ -9,6 +9,7 @@ SRC_URI  = "${KERNELORG_MIRROR}/linux/network/${BPN}/${BP}.tar.xz \
             file://CVE-2021-26675.patch \
             file://CVE-2021-26676-0001.patch \
             file://CVE-2021-26676-0002.patch \
+            file://CVE-2021-33833.patch \
             file://CVE-2022-23096-7.patch \
             file://CVE-2022-23098.patch \
 "