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authorHauke Mehrtens <hauke@hauke-m.de>2021-05-02 17:42:19 +0200
committerHauke Mehrtens <hauke@hauke-m.de>2021-05-04 22:29:29 +0200
commita641502849091feebf5d41c2eaa9ac89e59b8127 (patch)
tree505d6282214a319ded546a17a6866d58653fd256
parent701d25b551144cacd5d7fd8024fd2e6c7c264b70 (diff)
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busybox: backport fix for CVE-2021-28831
This backports a fix for the low priority CVE-2021-28831: decompress_gunzip.c in BusyBox through 1.32.1 mishandles the error bit on the huft_build result pointer, with a resultant invalid free or segmentation fault, via malformed gzip data. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> (cherry picked from commit 13397b2b95b4800fb0a29c3d483fa280d10f0eb0)
-rw-r--r--package/utils/busybox/Makefile2
-rw-r--r--package/utils/busybox/patches/005-backport-CVE-2021-28831.patch52
2 files changed, 53 insertions, 1 deletions
diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile
index 9df358ef78..58bc1e6795 100644
--- a/package/utils/busybox/Makefile
+++ b/package/utils/busybox/Makefile
@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
PKG_NAME:=busybox
PKG_VERSION:=1.33.0
-PKG_RELEASE:=2
+PKG_RELEASE:=3
PKG_FLAGS:=essential
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
diff --git a/package/utils/busybox/patches/005-backport-CVE-2021-28831.patch b/package/utils/busybox/patches/005-backport-CVE-2021-28831.patch
new file mode 100644
index 0000000000..7637679a69
--- /dev/null
+++ b/package/utils/busybox/patches/005-backport-CVE-2021-28831.patch
@@ -0,0 +1,52 @@
+From f25d254dfd4243698c31a4f3153d4ac72aa9e9bd Mon Sep 17 00:00:00 2001
+From: Samuel Sapalski <samuel.sapalski@nokia.com>
+Date: Wed, 3 Mar 2021 16:31:22 +0100
+Subject: 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>
+---
+ archival/libarchive/decompress_gunzip.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+--- 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_PAR
+ * 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)