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@@ -0,0 +1,96 @@
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+Heap-based Buffer Overflow in the psf_binheader_writef function in common.c in
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+libsndfile through 1.0.28 allows remote attackers to cause a denial of service
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+(application crash) or possibly have unspecified other impact.
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+
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+CVE: CVE-2017-12562
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+Upstream-Status: Backport [cf7a8182c2642c50f1cf90dddea9ce96a8bad2e8]
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+Signed-off-by: Ross Burton <ross.burton@intel.com>
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+
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+From b6a9d7e95888ffa77d8c75ce3f03e6c7165587cd Mon Sep 17 00:00:00 2001
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+From: =?UTF-8?q?J=C3=B6rn=20Heusipp?= <osmanx@problemloesungsmaschine.de>
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+Date: Wed, 14 Jun 2017 12:25:40 +0200
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+Subject: [PATCH] src/common.c: Fix heap buffer overflows when writing strings
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+ in binheader
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+
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+Fixes the following problems:
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+ 1. Case 's' only enlarges the buffer by 16 bytes instead of size bytes.
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+ 2. psf_binheader_writef() enlarges the header buffer (if needed) prior to the
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+ big switch statement by an amount (16 bytes) which is enough for all cases
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+ where only a single value gets added. Cases 's', 'S', 'p' however
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+ additionally write an arbitrary length block of data and again enlarge the
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+ buffer to the required amount. However, the required space calculation does
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+ not take into account the size of the length field which gets output before
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+ the data.
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+ 3. Buffer size requirement calculation in case 'S' does not account for the
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+ padding byte ("size += (size & 1) ;" happens after the calculation which
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+ uses "size").
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+ 4. Case 'S' can overrun the header buffer by 1 byte when no padding is
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+ involved
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+ ("memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + 1) ;" while
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+ the buffer is only guaranteed to have "size" space available).
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+ 5. "psf->header.ptr [psf->header.indx] = 0 ;" in case 'S' always writes 1 byte
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+ beyond the space which is guaranteed to be allocated in the header buffer.
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+ 6. Case 's' can overrun the provided source string by 1 byte if padding is
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+ involved ("memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size) ;"
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+ where "size" is "strlen (strptr) + 1" (which includes the 0 terminator,
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+ plus optionally another 1 which is padding and not guaranteed to be
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+ readable via the source string pointer).
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+
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+Closes: https://github.com/erikd/libsndfile/issues/292
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+---
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+ src/common.c | 15 +++++++--------
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+ 1 file changed, 7 insertions(+), 8 deletions(-)
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+
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+diff --git a/src/common.c b/src/common.c
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+index 1a6204ca..6b2a2ee9 100644
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+--- a/src/common.c
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++++ b/src/common.c
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+@@ -681,16 +681,16 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
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+ /* Write a C string (guaranteed to have a zero terminator). */
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+ strptr = va_arg (argptr, char *) ;
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+ size = strlen (strptr) + 1 ;
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+- size += (size & 1) ;
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+
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+- if (psf->header.indx + (sf_count_t) size >= psf->header.len && psf_bump_header_allocation (psf, 16))
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++ 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)))
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+ return count ;
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+
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+ if (psf->rwf_endian == SF_ENDIAN_BIG)
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+- header_put_be_int (psf, size) ;
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++ header_put_be_int (psf, size + (size & 1)) ;
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+ else
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+- header_put_le_int (psf, size) ;
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++ header_put_le_int (psf, size + (size & 1)) ;
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+ memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size) ;
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++ size += (size & 1) ;
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+ psf->header.indx += size ;
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+ psf->header.ptr [psf->header.indx - 1] = 0 ;
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+ count += 4 + size ;
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+@@ -703,16 +703,15 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
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+ */
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+ strptr = va_arg (argptr, char *) ;
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+ size = strlen (strptr) ;
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+- if (psf->header.indx + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, size))
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++ 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)))
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+ return count ;
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+ if (psf->rwf_endian == SF_ENDIAN_BIG)
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+ header_put_be_int (psf, size) ;
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+ else
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+ header_put_le_int (psf, size) ;
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+- memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + 1) ;
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++ memcpy (&(psf->header.ptr [psf->header.indx]), strptr, size + (size & 1)) ;
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+ size += (size & 1) ;
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+ psf->header.indx += size ;
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+- psf->header.ptr [psf->header.indx] = 0 ;
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+ count += 4 + size ;
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+ break ;
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+
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+@@ -724,7 +723,7 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
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+ size = (size & 1) ? size : size + 1 ;
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+ size = (size > 254) ? 254 : size ;
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+
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+- if (psf->header.indx + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, size))
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++ if (psf->header.indx + 1 + (sf_count_t) size > psf->header.len && psf_bump_header_allocation (psf, 1 + size))
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+ return count ;
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+
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+ header_put_byte (psf, size) ;
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Ross Burton