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authorPaul Pluzhnikov <ppluzhnikov@google.com>2015-02-06 00:30:42 -0500
committerCarlos O'Donell <carlos@systemhalted.org>2015-02-06 00:34:51 -0500
commit5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06 (patch)
treea77a8efbf88a4eed15cfefe4e5d570d380985c1c /stdio-common/vfscanf.c
parent04cb913ddf67ac90da274dd32b6ceafd57ca36ca (diff)
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CVE-2015-1472: wscanf allocates too little memory
BZ #16618 Under certain conditions wscanf can allocate too little memory for the to-be-scanned arguments and overflow the allocated buffer. The implementation now correctly computes the required buffer size when using malloc. A regression test was added to tst-sscanf.
Diffstat (limited to 'stdio-common/vfscanf.c')
-rw-r--r--stdio-common/vfscanf.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
index cd129a81de..0e204e7b32 100644
--- a/stdio-common/vfscanf.c
+++ b/stdio-common/vfscanf.c
@@ -272,9 +272,10 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr,
if (__glibc_unlikely (wpsize == wpmax)) \
{ \
CHAR_T *old = wp; \
- size_t newsize = (UCHAR_MAX + 1 > 2 * wpmax \
- ? UCHAR_MAX + 1 : 2 * wpmax); \
- if (use_malloc || !__libc_use_alloca (newsize)) \
+ bool fits = __glibc_likely (wpmax <= SIZE_MAX / sizeof (CHAR_T) / 2); \
+ size_t wpneed = MAX (UCHAR_MAX + 1, 2 * wpmax); \
+ size_t newsize = fits ? wpneed * sizeof (CHAR_T) : SIZE_MAX; \
+ if (!__libc_use_alloca (newsize)) \
{ \
wp = realloc (use_malloc ? wp : NULL, newsize); \
if (wp == NULL) \
@@ -286,14 +287,13 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr,
} \
if (! use_malloc) \
MEMCPY (wp, old, wpsize); \
- wpmax = newsize; \
+ wpmax = wpneed; \
use_malloc = true; \
} \
else \
{ \
size_t s = wpmax * sizeof (CHAR_T); \
- wp = (CHAR_T *) extend_alloca (wp, s, \
- newsize * sizeof (CHAR_T)); \
+ wp = (CHAR_T *) extend_alloca (wp, s, newsize); \
wpmax = s / sizeof (CHAR_T); \
if (old != NULL) \
MEMCPY (wp, old, wpsize); \