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| author | Bruno Haible <bruno@clisp.org> | 2018-09-23 14:13:52 +0200 |
|---|---|---|
| committer | Bruno Haible <bruno@clisp.org> | 2018-09-23 14:15:03 +0200 |
| commit | 278b4175c9d7dd47c1a3071554aac02add3b3c35 (patch) | |
| tree | 7bf2ed8b084f6fecbd1c78e946ece9d7211e233b /lib/vasnprintf.c | |
| parent | 9e43f06a96907348ac6729dcddf8fddc08469ab3 (diff) | |
| download | gnulib-278b4175c9d7dd47c1a3071554aac02add3b3c35.tar.gz | |
vasnprintf: Fix heap memory overrun bug.
Reported by Ben Pfaff <blp@cs.stanford.edu> in
<https://lists.gnu.org/archive/html/bug-gnulib/2018-09/msg00107.html>.
* lib/vasnprintf.c (convert_to_decimal): Allocate one more byte of
memory.
* tests/test-vasnprintf.c (test_function): Add another test.
Diffstat (limited to 'lib/vasnprintf.c')
| -rw-r--r-- | lib/vasnprintf.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c index 56ffbe308a..30d021b284 100644 --- a/lib/vasnprintf.c +++ b/lib/vasnprintf.c @@ -860,7 +860,9 @@ convert_to_decimal (mpn_t a, size_t extra_zeroes) size_t a_len = a.nlimbs; /* 0.03345 is slightly larger than log(2)/(9*log(10)). */ size_t c_len = 9 * ((size_t)(a_len * (GMP_LIMB_BITS * 0.03345f)) + 1); - char *c_ptr = (char *) malloc (xsum (c_len, extra_zeroes)); + /* We need extra_zeroes bytes for zeroes, followed by c_len bytes for the + digits of a, followed by 1 byte for the terminating NUL. */ + char *c_ptr = (char *) malloc (xsum (xsum (extra_zeroes, c_len), 1)); if (c_ptr != NULL) { char *d_ptr = c_ptr; |