[Buildroot] [PATCH] package/libsndfile: add security patch for CVE-2021-3246

[Peter Korsgaard <peter@korsgaard.com>]

A heap buffer overflow vulnerability in msadpcm_decode_block of libsndfile
1.0.30 allows attackers to execute arbitrary code via a crafted WAV file.

https://nvd.nist.gov/vuln/detail/CVE-2021-3246

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
 ...-ms_adpcm-Fix-and-extend-size-checks.patch | 40 +++++++++++++++++++
 package/libsndfile/libsndfile.mk              |  3 ++
 2 files changed, 43 insertions(+)
 create mode 100644 package/libsndfile/0001-ms_adpcm-Fix-and-extend-size-checks.patch

diff --git a/package/libsndfile/0001-ms_adpcm-Fix-and-extend-size-checks.patch b/package/libsndfile/0001-ms_adpcm-Fix-and-extend-size-checks.patch
new file mode 100644
index 0000000000..edacbda01a
--- /dev/null
+++ b/package/libsndfile/0001-ms_adpcm-Fix-and-extend-size-checks.patch
@@ -0,0 +1,40 @@
+From deb669ee8be55a94565f6f8a6b60890c2e7c6f32 Mon Sep 17 00:00:00 2001
+From: bobsayshilol <bobsayshilol@live.co.uk>
+Date: Thu, 18 Feb 2021 21:52:09 +0000
+Subject: [PATCH] ms_adpcm: Fix and extend size checks
+
+'blockalign' is the size of a block, and each block contains 7 samples
+per channel as part of the preamble, so check against 'samplesperblock'
+rather than 'blockalign'. Also add an additional check that the block
+is big enough to hold the samples it claims to hold.
+
+https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26803
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ src/ms_adpcm.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/src/ms_adpcm.c b/src/ms_adpcm.c
+index 5e8f1a31..a21cb994 100644
+--- a/src/ms_adpcm.c
++++ b/src/ms_adpcm.c
+@@ -128,8 +128,14 @@ wavlike_msadpcm_init	(SF_PRIVATE *psf, int blockalign, int samplesperblock)
+ 	if (psf->file.mode == SFM_WRITE)
+ 		samplesperblock = 2 + 2 * (blockalign - 7 * psf->sf.channels) / psf->sf.channels ;
+ 
+-	if (blockalign < 7 * psf->sf.channels)
+-	{	psf_log_printf (psf, "*** Error blockalign (%d) should be > %d.\n", blockalign, 7 * psf->sf.channels) ;
++	/* There's 7 samples per channel in the preamble of each block */
++	if (samplesperblock < 7 * psf->sf.channels)
++	{	psf_log_printf (psf, "*** Error samplesperblock (%d) should be >= %d.\n", samplesperblock, 7 * psf->sf.channels) ;
++		return SFE_INTERNAL ;
++		} ;
++
++	if (2 * blockalign < samplesperblock * psf->sf.channels)
++	{	psf_log_printf (psf, "*** Error blockalign (%d) should be >= %d.\n", blockalign, samplesperblock * psf->sf.channels / 2) ;
+ 		return SFE_INTERNAL ;
+ 		} ;
+ 
+-- 
+2.20.1
+
diff --git a/package/libsndfile/libsndfile.mk b/package/libsndfile/libsndfile.mk
index c955b9d088..ed9e8e3d14 100644
--- a/package/libsndfile/libsndfile.mk
+++ b/package/libsndfile/libsndfile.mk
@@ -12,6 +12,9 @@ LIBSNDFILE_LICENSE = LGPL-2.1+
 LIBSNDFILE_LICENSE_FILES = COPYING
 LIBSNDFILE_CPE_ID_VENDOR = libsndfile_project
 
+# 0001-ms_adpcm-Fix-and-extend-size-checks.patch
+LIBSNDFILE_IGNORE_CVES += CVE-2021-3246
+
 # disputed, https://github.com/erikd/libsndfile/issues/398
 LIBSNDFILE_IGNORE_CVES += CVE-2018-13419
 
-- 
2.20.1

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