busybox: fix CVE-2021-28831

Backport patch to fix CVE-2021-28831.

(From OE-Core rev: e579dbd9a6b2472ca90f411c0b594da9e38c9aca)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 60 insertions, 1 deletions

diff --git a/meta/recipes-core/busybox/busybox/0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch b/meta/recipes-core/busybox/busybox/0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch
new file mode 100644
index 0000000000..67c9f189cc
--- /dev/null
+++ b/meta/recipes-core/busybox/busybox/0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch
@@ -0,0 +1,58 @@
+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
+Signed-off-by: Chen Qi <Qi.Chen@windriver.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;
+@@ -289,8 +299,6 @@ static unsigned fill_bitbuffer(STATE_PARAM unsigned bitbuffer, unsigned *current
+  * or a valid pointer to a Huffman table, ORed with 0x1 if incompete table
+  * is given: "fixed inflate" decoder feeds us such data.
+  */
+-#define BAD_HUFT(p) ((uintptr_t)(p) & 1)
+-#define ERR_RET     ((huft_t*)(uintptr_t)1)
+ static huft_t* huft_build(const unsigned *b, const unsigned n,
+                        const unsigned s, const struct cp_ext *cp_ext,
+                        unsigned *m)
diff --git a/meta/recipes-core/busybox/busybox_1.33.0.bb b/meta/recipes-core/busybox/busybox_1.33.0.bb
index 1a3f218bca..58e9cf7fce 100644
--- a/meta/recipes-core/busybox/busybox_1.33.0.bb
+++ b/meta/recipes-core/busybox/busybox_1.33.0.bb
@@ -46,7 +46,8 @@ 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://rev.cfg \
            file://pgrep.cfg \
-"
+           file://0001-decompress_gunzip-Fix-DoS-if-gzip-is-corrupt.patch \
+           "
 SRC_URI_append_libc-musl = " file://musl.cfg "
 
 SRC_URI[tarball.sha256sum] = "d568681c91a85edc6710770cebc1e80e042ad74d305b5c2e6d57a5f3de3b8fbd"