89 lines
4.3 KiB
Diff
89 lines
4.3 KiB
Diff
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(-)
|
|
|
|
diff --git a/src/common.c b/src/common.c
|
|
index 1a6204ca..6b2a2ee9 100644
|
|
--- a/src/common.c
|
|
+++ b/src/common.c
|
|
@@ -681,16 +681,16 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
|
|
/* 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 ;
|
|
@@ -703,16 +703,15 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
|
|
*/
|
|
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 ;
|
|
|
|
@@ -724,7 +723,7 @@ psf_binheader_writef (SF_PRIVATE *psf, const char *format, ...)
|
|
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) ;
|