diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | NEWS | 24 | ||||
| -rw-r--r-- | stdio-common/tst-sscanf.c | 33 | ||||
| -rw-r--r-- | stdio-common/vfscanf.c | 12 |
4 files changed, 62 insertions, 15 deletions
@@ -1,3 +1,11 @@ +2015-02-05 Paul Pluzhnikov <ppluzhnikov@google.com> + + [BZ #16618] + * stdio-common/tst-sscanf.c (main): Test for buffer overflow. + * stdio-common/vfscanf.c (_IO_vfscanf_internal): Compute needed + size in bytes. Store needed elements in wpmax. Use needed size + in bytes for extend_alloca. + 2015-02-05 Carlos O'Donell <carlos@systemhalted.org> * manual/install.texi: Latest tested versions are GCC 4.9.2, @@ -10,15 +10,21 @@ Version 2.21 * The following bugs are resolved with this release: 6652, 10672, 12674, 12847, 12926, 13862, 14132, 14138, 14171, 14498, - 15215, 15378, 15884, 16009, 16418, 16191, 16469, 16576, 16617, 16619, - 16657, 16740, 16857, 17192, 17266, 17273, 17344, 17363, 17370, 17371, - 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, - 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585, 17589, 17594, - 17601, 17608, 17616, 17625, 17630, 17633, 17634, 17635, 17647, 17653, - 17657, 17658, 17664, 17665, 17668, 17682, 17702, 17717, 17719, 17722, - 17723, 17724, 17725, 17732, 17733, 17744, 17745, 17746, 17747, 17748, - 17775, 17777, 17780, 17781, 17782, 17791, 17793, 17796, 17797, 17801, - 17803, 17806, 17834, 17844, 17848, 17868, 17869, 17870, 17885, 17892. + 15215, 15378, 15884, 16009, 16418, 16191, 16469, 16576, 16617, 16618, + 16619, 16657, 16740, 16857, 17192, 17266, 17273, 17344, 17363, 17370, + 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, + 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585, 17589, + 17594, 17601, 17608, 17616, 17625, 17630, 17633, 17634, 17635, 17647, + 17653, 17657, 17658, 17664, 17665, 17668, 17682, 17702, 17717, 17719, + 17722, 17723, 17724, 17725, 17732, 17733, 17744, 17745, 17746, 17747, + 17748, 17775, 17777, 17780, 17781, 17782, 17791, 17793, 17796, 17797, + 17801, 17803, 17806, 17834, 17844, 17848, 17868, 17869, 17870, 17885, + 17892. + +* CVE-2015-1472 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 new semaphore algorithm has been implemented in generic C code for all machines. Previous custom assembly implementations of semaphore were diff --git a/stdio-common/tst-sscanf.c b/stdio-common/tst-sscanf.c index aece3f2f29..8a2eb9e39c 100644 --- a/stdio-common/tst-sscanf.c +++ b/stdio-common/tst-sscanf.c @@ -233,5 +233,38 @@ 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; } 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); \ |