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Backport fix for wscanf Tested:

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This commit is contained in:
Stan Shebs 2015-03-13 15:29:01 -07:00
parent d37331c9ef
commit 2963bd873f
3 changed files with 44 additions and 6 deletions
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5
README.google
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@ -424,3 +424,8 @@ resolv/res_libc.c
resolv/nss_dns/dns-resolve.c
For b/18752432, backport infinite loop fix in getnetbyname (PR17630)
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=11e3417af6e354f1942c68a271ae51e892b2814d
stdio-common/tst-sscanf.c
stdio-common/vfscanf.c
For b/19289207, backport memory allocation fix for wscanf (PR16618)
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06

33
stdio-common/tst-sscanf.c
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@ -232,5 +232,38 @@ main (void)
}
}
/* BZ #16618
The test will segfault during SSCANF if the buffer overflow
is not fixed. The size of `s` is such that it forces the use
of malloc internally and this triggers the incorrect computation.
Thus the value for SIZE is arbitrariy high enough that malloc
is used. */
{
#define SIZE 131072
CHAR *s = malloc ((SIZE + 1) * sizeof (*s));
if (s == NULL)
abort ();
for (size_t i = 0; i < SIZE; i++)
s[i] = L('0');
s[SIZE] = L('\0');
int i = 42;
/* Scan multi-digit zero into `i`. */
if (SSCANF (s, L("%d"), &i) != 1)
{
printf ("FAIL: bug16618: SSCANF did not read one input item.\n");
result = 1;
}
if (i != 0)
{
printf ("FAIL: bug16618: Value of `i` was not zero as expected.\n");
result = 1;
}
free (s);
if (result != 1)
printf ("PASS: bug16618: Did not crash.\n");
#undef SIZE
}
return result;
}

12
stdio-common/vfscanf.c
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@ -272,9 +272,10 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr,
if (__builtin_expect (wpsize == wpmax, 0)) \
{ \
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); \