Mercurial > gnulib
changeset 39866:97ddb1ab5d88
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.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Sun, 23 Sep 2018 14:13:52 +0200 |
parents | f1164387ff3c |
children | 67c6a0f59621 |
files | ChangeLog lib/vasnprintf.c tests/test-vasnprintf.c |
diffstat | 3 files changed, 32 insertions(+), 2 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog Sat Sep 22 08:45:27 2018 -0700 +++ b/ChangeLog Sun Sep 23 14:13:52 2018 +0200 @@ -1,3 +1,12 @@ +2018-09-23 Bruno Haible <bruno@clisp.org> + + 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. + 2018-09-19 Paul Eggert <eggert@cs.ucla.edu> maint: mktime.c now shared with glibc
--- a/lib/vasnprintf.c Sat Sep 22 08:45:27 2018 -0700 +++ b/lib/vasnprintf.c Sun Sep 23 14:13:52 2018 +0200 @@ -860,7 +860,9 @@ 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;
--- a/tests/test-vasnprintf.c Sat Sep 22 08:45:27 2018 -0700 +++ b/tests/test-vasnprintf.c Sun Sep 23 14:13:52 2018 +0200 @@ -53,7 +53,26 @@ ASSERT (result != NULL); ASSERT (strcmp (result, "12345") == 0); ASSERT (length == 5); - if (size < 6) + if (size < 5 + 1) + ASSERT (result != buf); + ASSERT (memcmp (buf + size, &"DEADBEEF"[size], 8 - size) == 0); + if (result != buf) + free (result); + } + + /* Note: This test assumes IEEE 754 representation of 'double' floats. */ + for (size = 0; size <= 8; size++) + { + size_t length; + char *result; + + memcpy (buf, "DEADBEEF", 8); + length = size; + result = my_asnprintf (buf, &length, "%2.0f", 1.6314159265358979e+125); + ASSERT (result != NULL); + ASSERT (strcmp (result, "163141592653589790215729350939528493057529598899734151772468186268423257777068536614838678161083520756952076273094236944990208") == 0); + ASSERT (length == 126); + if (size < 126 + 1) ASSERT (result != buf); ASSERT (memcmp (buf + size, &"DEADBEEF"[size], 8 - size) == 0); if (result != buf)