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From: Andrew Morton <akpm@linux-foundation.org>
To: terrelln@fb.com,stable@vger.kernel.org,hsiangkao@linux.alibaba.com,cy.fan@huawei.com,cyan@fb.com,guoxuenan@huawei.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org
Subject: [patch 3/9] lz4: fix LZ4_decompress_safe_partial read out of bound
Date: Fri, 08 Apr 2022 13:08:58 -0700	[thread overview]
Message-ID: <20220408200859.80FFFC385A6@smtp.kernel.org> (raw)
In-Reply-To: <20220408130819.a89195e527ce58dfbe0700b9@linux-foundation.org>

From: Guo Xuenan <guoxuenan@huawei.com>
Subject: lz4: fix LZ4_decompress_safe_partial read out of bound

When partialDecoding, it is EOF if we've either filled the output buffer
or can't proceed with reading an offset for following match.

In some extreme corner cases when compressed data is suitably
corrupted, UAF will occur.  As reported by KASAN [1],
LZ4_decompress_safe_partial may lead to read out of bound problem
during decoding.  lz4 upstream has fixed it [2] and this issue has been
disscussed here [3] before.

current decompression routine was ported from lz4 v1.8.3, bumping lib/lz4
to v1.9.+ is certainly a huge work to be done later, so, we'd better fix
it first.

[1] https://lore.kernel.org/all/000000000000830d1205cf7f0477@google.com/
[2] https://github.com/lz4/lz4/commit/c5d6f8a8be3927c0bec91bcc58667a6cfad244ad#
[3] https://lore.kernel.org/all/CC666AE8-4CA4-4951-B6FB-A2EFDE3AC03B@fb.com/

Link: https://lkml.kernel.org/r/20211111105048.2006070-1-guoxuenan@huawei.com
Reported-by: syzbot+63d688f1d899c588fb71@syzkaller.appspotmail.com
Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Nick Terrell <terrelln@fb.com>
Acked-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Yann Collet <cyan@fb.com>
Cc: Chengyang Fan <cy.fan@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/lz4/lz4_decompress.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/lib/lz4/lz4_decompress.c~lz4-fix-lz4_decompress_safe_partial-read-out-of-bound
+++ a/lib/lz4/lz4_decompress.c
@@ -271,8 +271,12 @@ static FORCE_INLINE int LZ4_decompress_g
 			ip += length;
 			op += length;
 
-			/* Necessarily EOF, due to parsing restrictions */
-			if (!partialDecoding || (cpy == oend))
+			/* Necessarily EOF when !partialDecoding.
+			 * When partialDecoding, it is EOF if we've either
+			 * filled the output buffer or
+			 * can't proceed with reading an offset for following match.
+			 */
+			if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2)))
 				break;
 		} else {
 			/* may overwrite up to WILDCOPYLENGTH beyond cpy */
_

WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: terrelln@fb.com, stable@vger.kernel.org,
	hsiangkao@linux.alibaba.com, cy.fan@huawei.com, cyan@fb.com,
	guoxuenan@huawei.com, akpm@linux-foundation.org,
	patches@lists.linux.dev, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org
Subject: [patch 3/9] lz4: fix LZ4_decompress_safe_partial read out of bound
Date: Fri, 08 Apr 2022 13:08:58 -0700	[thread overview]
Message-ID: <20220408200859.80FFFC385A6@smtp.kernel.org> (raw)
In-Reply-To: <20220408130819.a89195e527ce58dfbe0700b9@linux-foundation.org>

From: Guo Xuenan <guoxuenan@huawei.com>
Subject: lz4: fix LZ4_decompress_safe_partial read out of bound

When partialDecoding, it is EOF if we've either filled the output buffer
or can't proceed with reading an offset for following match.

In some extreme corner cases when compressed data is suitably
corrupted, UAF will occur.  As reported by KASAN [1],
LZ4_decompress_safe_partial may lead to read out of bound problem
during decoding.  lz4 upstream has fixed it [2] and this issue has been
disscussed here [3] before.

current decompression routine was ported from lz4 v1.8.3, bumping lib/lz4
to v1.9.+ is certainly a huge work to be done later, so, we'd better fix
it first.

[1] https://lore.kernel.org/all/000000000000830d1205cf7f0477@google.com/
[2] https://github.com/lz4/lz4/commit/c5d6f8a8be3927c0bec91bcc58667a6cfad244ad#
[3] https://lore.kernel.org/all/CC666AE8-4CA4-4951-B6FB-A2EFDE3AC03B@fb.com/

Link: https://lkml.kernel.org/r/20211111105048.2006070-1-guoxuenan@huawei.com
Reported-by: syzbot+63d688f1d899c588fb71@syzkaller.appspotmail.com
Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Nick Terrell <terrelln@fb.com>
Acked-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Yann Collet <cyan@fb.com>
Cc: Chengyang Fan <cy.fan@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/lz4/lz4_decompress.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/lib/lz4/lz4_decompress.c~lz4-fix-lz4_decompress_safe_partial-read-out-of-bound
+++ a/lib/lz4/lz4_decompress.c
@@ -271,8 +271,12 @@ static FORCE_INLINE int LZ4_decompress_g
 			ip += length;
 			op += length;
 
-			/* Necessarily EOF, due to parsing restrictions */
-			if (!partialDecoding || (cpy == oend))
+			/* Necessarily EOF when !partialDecoding.
+			 * When partialDecoding, it is EOF if we've either
+			 * filled the output buffer or
+			 * can't proceed with reading an offset for following match.
+			 */
+			if (!partialDecoding || (cpy == oend) || (ip >= (iend - 2)))
 				break;
 		} else {
 			/* may overwrite up to WILDCOPYLENGTH beyond cpy */
_

  parent reply	other threads:[~2022-04-08 20:08 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08 20:08 incoming Andrew Morton
2022-04-08 20:08 ` [patch 1/9] mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation Andrew Morton
2022-04-08 20:08   ` Andrew Morton
2022-04-08 20:10   ` Matthew Wilcox
2022-04-08 20:08 ` [patch 2/9] highmem: fix checks in __kmap_local_sched_{in,out} Andrew Morton
2022-04-08 20:08   ` Andrew Morton
2022-04-08 20:08 ` Andrew Morton [this message]
2022-04-08 20:08   ` [patch 3/9] lz4: fix LZ4_decompress_safe_partial read out of bound Andrew Morton
2022-04-08 20:09 ` [patch 4/9] mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning Andrew Morton
2022-04-08 20:09   ` Andrew Morton
2022-04-11  9:00   ` Oscar Salvador
2022-04-08 20:09 ` [patch 5/9] mmmremap.c: avoid pointless invalidate_range_start/end on mremap(old_size=0) Andrew Morton
2022-04-08 20:09   ` Andrew Morton
2022-04-08 20:09 ` [patch 6/9] mm/mempolicy: fix mpol_new leak in shared_policy_replace Andrew Morton
2022-04-08 20:09   ` Andrew Morton
2022-04-08 20:09 ` [patch 7/9] mailmap: update Vasily Averin's email address Andrew Morton
2022-04-08 20:09   ` Andrew Morton
2022-04-08 20:09 ` [patch 8/9] mm/list_lru.c: revert "mm/list_lru: optimize memcg_reparent_list_lru_node()" Andrew Morton
2022-04-08 20:09   ` Andrew Morton
2022-04-08 20:09 ` [patch 9/9] MAINTAINERS: add Tom as clang reviewer Andrew Morton
2022-04-08 20:09   ` Andrew Morton

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