busybox: fix CVE-2021-28831

Backport patch to fix CVE-2021-28831.

(From OE-Core rev: e579dbd9a6b2472ca90f411c0b594da9e38c9aca)

(From OE-Core rev: 42098fd740fe3de68a221fcc9c44ead545757461)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Akash Hadke <akash.hadke@kpit.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/busybox/busybox/0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch

@@ -0,0 +1,51 @@
+From fe791386ebc270219ca00406c9fdadc5130b64ee Mon Sep 17 00:00:00 2001
+From: Samuel Sapalski <samuel.sapalski@nokia.com>
+Date: Wed, 3 Mar 2021 16:31:22 +0100
+Subject: [PATCH] decompress_gunzip: Fix DoS if gzip is corrupt
+
+On certain corrupt gzip files, huft_build will set the error bit on
+the result pointer. If afterwards abort_unzip is called huft_free
+might run into a segmentation fault or an invalid pointer to
+free(p).
+
+In order to mitigate this, we check in huft_free if the error bit
+is set and clear it before the linked list is freed.
+
+Signed-off-by: Samuel Sapalski <samuel.sapalski@nokia.com>
+Signed-off-by: Peter Kaestle <peter.kaestle@nokia.com>
+Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
+
+Upstream-Status: Backport
+CVE: CVE-2021-28831
+Comment: One hunk from this patch is removed as it was not relevant.
+Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
+Signed-off-by: Akash Hadke <Akash.Hadke@kpit.com>
+---
+ archival/libarchive/decompress_gunzip.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c
+index eb3b64930..e93cd5005 100644
+--- a/archival/libarchive/decompress_gunzip.c
++++ b/archival/libarchive/decompress_gunzip.c
+@@ -220,10 +220,20 @@ static const uint8_t border[] ALIGN1 = {
+  * each table.
+  * t: table to free
+  */
++#define BAD_HUFT(p) ((uintptr_t)(p) & 1)
++#define ERR_RET     ((huft_t*)(uintptr_t)1)
+ static void huft_free(huft_t *p)
+ {
+ 	huft_t *q;
+ 
++	/*
++	 * If 'p' has the error bit set we have to clear it, otherwise we might run
++	 * into a segmentation fault or an invalid pointer to free(p)
++	 */
++	if (BAD_HUFT(p)) {
++		p = (huft_t*)((uintptr_t)(p) ^ (uintptr_t)(ERR_RET));
++	}
++
+ 	/* Go through linked list, freeing from the malloced (t[-1]) address. */
+ 	while (p) {
+ 		q = (--p)->v.t;

meta/recipes-core/busybox/busybox_1.31.1.bb

@@ -50,7 +50,8 @@ SRC_URI = "https://busybox.net/downloads/busybox-${PV}.tar.bz2;name=tarball \
            file://0001-sysctl-ignore-EIO-of-stable_secret-below-proc-sys-ne.patch \
            file://busybox-CVE-2018-1000500.patch \
            file://0001-hwclock-make-glibc-2.31-compatible.patch \
-"
+           file://0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch \
+           "
 SRC_URI_append_libc-musl = " file://musl.cfg "
 
 SRC_URI[tarball.md5sum] = "70913edaf2263a157393af07565c17f0"