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Accepting request 515150 from home:tiwai:branches:multimedia:libs

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- Fix Heap-based Buffer Overflow in the psf_binheader_writef
  (CVE-2017-12562, bsc#1052476):
  0020-src-common.c-Fix-heap-buffer-overflows-when-writing-.patch

OBS-URL: https://build.opensuse.org/request/show/515150
OBS-URL: https://build.opensuse.org/package/show/multimedia:libs/libsndfile?expand=0&rev=62
This commit is contained in:
Takashi Iwai 2017-08-08 09:26:19 +00:00 committed by Git OBS Bridge
parent 660458140b
commit b1e542206b
3 changed files with 95 additions and 0 deletions
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86
0020-src-common.c-Fix-heap-buffer-overflows-when-writing-.patch Normal file
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@ -0,0 +1,86 @@
From cf7a8182c2642c50f1cf90dddea9ce96a8bad2e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn=20Heusipp?= <osmanx@problemloesungsmaschine.de>
Date: Wed, 14 Jun 2017 12:25:40 +0200
Subject: [PATCH] src/common.c: Fix heap buffer overflows when writing strings
in binheader
Fixes the following problems:
1. Case 's' only enlarges the buffer by 16 bytes instead of size bytes.
2. psf_binheader_writef() enlarges the header buffer (if needed) prior to the
big switch statement by an amount (16 bytes) which is enough for all cases
where only a single value gets added. Cases 's', 'S', 'p' however
additionally write an arbitrary length block of data and again enlarge the
buffer to the required amount. However, the required space calculation does
not take into account the size of the length field which gets output before
the data.
3. Buffer size requirement calculation in case 'S' does not account for the
padding byte ("size += (size & 1) ;" happens after the calculation which
uses "size").
4. Case 'S' can overrun the header buffer by 1 byte when no padding is
involved
("memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + 1) ;" while
the buffer is only guaranteed to have "size" space available).
5. "psf->header.ptr [psf->header.indx] = 0 ;" in case 'S' always writes 1 byte
beyond the space which is guaranteed to be allocated in the header buffer.
6. Case 's' can overrun the provided source string by 1 byte if padding is
involved ("memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size) ;"
where "size" is "strlen (strptr) + 1" (which includes the 0 terminator,
plus optionally another 1 which is padding and not guaranteed to be
readable via the source string pointer).
Closes: https://github.com/erikd/libsndfile/issues/292
---
src/common.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/src/common.c
+++ b/src/common.c
@@ -675,16 +675,16 @@ psf_binheader_writef (SF_PRIVATE *psf, c
/* Write a C string (guaranteed to have a zero terminator). */
strptr = va_arg (argptr, char *) ;
size = strlen (strptr) + 1 ;
- size += (size & 1) ;
- if (psf->header.indx + (sf_count_t) size >= psf->header.len && psf_bump_header_allocation (psf, 16))
+ if (psf->header.indx + 4 + (sf_count_t) size + (sf_count_t) (size & 1) > psf->header.len && psf_bump_header_allocation (psf, 4 + size + (size & 1)))
return count ;
if (psf->rwf_endian == SF_ENDIAN_BIG)
- header_put_be_int (psf, size) ;
+ header_put_be_int (psf, size + (size & 1)) ;
else
- header_put_le_int (psf, size) ;
+ header_put_le_int (psf, size + (size & 1)) ;
memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size) ;
+ size += (size & 1) ;
psf->header.indx += size ;
psf->header.ptr [psf->header.indx - 1] = 0 ;
count += 4 + size ;
@@ -697,16 +697,15 @@ psf_binheader_writef (SF_PRIVATE *psf, c
*/
strptr = va_arg (argptr, char *) ;
size = strlen (strptr) ;
- if (psf->header.indx + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, size))
+ if (psf->header.indx + 4 + (sf_count_t) size + (sf_count_t) (size & 1) > psf->header.len && psf_bump_header_allocation (psf, 4 + size + (size & 1)))
return count ;
if (psf->rwf_endian == SF_ENDIAN_BIG)
header_put_be_int (psf, size) ;
else
header_put_le_int (psf, size) ;
- memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + 1) ;
+ memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + (size & 1)) ;
size += (size & 1) ;
psf->header.indx += size ;
- psf->header.ptr [psf->header.indx] = 0 ;
count += 4 + size ;
break ;
@@ -718,7 +717,7 @@ psf_binheader_writef (SF_PRIVATE *psf, c
size = (size & 1) ? size : size + 1 ;
size = (size > 254) ? 254 : size ;
- if (psf->header.indx + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, size))
+ if (psf->header.indx + 1 + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, 1 + size))
return count ;
header_put_byte (psf, size) ;

7
libsndfile.changes
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@ -1,3 +1,10 @@
-------------------------------------------------------------------
Tue Aug 8 11:00:09 CEST 2017 - tiwai@suse.de
- Fix Heap-based Buffer Overflow in the psf_binheader_writef
(CVE-2017-12562, bsc#1052476):
0020-src-common.c-Fix-heap-buffer-overflows-when-writing-.patch
-------------------------------------------------------------------
Tue Jun 13 08:36:52 CEST 2017 - tiwai@suse.de

2
libsndfile.spec
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@ -32,6 +32,7 @@ Source3: baselibs.conf
Patch1: 0001-FLAC-Fix-a-buffer-read-overrun.patch
Patch2: 0002-src-flac.c-Fix-a-buffer-read-overflow.patch
Patch10: 0010-src-aiff.c-Fix-a-buffer-read-overflow.patch
Patch20: 0020-src-common.c-Fix-heap-buffer-overflows-when-writing-.patch
# PATCH-FIX-OPENSUSE
Patch100: sndfile-ocloexec.patch
BuildRequires: alsa-devel
@ -82,6 +83,7 @@ libsndfile library.
%patch1 -p1
%patch2 -p1
%patch10 -p1
%patch20 -p1
%patch100 -p1
%build