summaryrefslogtreecommitdiff
path: root/builtin-name-rev.c
diff options
context:
space:
mode:
authorAndy Whitcroft <apw@shadowen.org>2007-05-15 17:33:25 +0100
committerJunio C Hamano <junkio@cox.net>2007-05-15 18:14:42 -0700
commitcf606e3ddd8666b990a6560be77eb9f28af0e47d (patch)
tree4cf1c85058ac12ff55e61870b5220b5f7c2d000a /builtin-name-rev.c
parent045fe3ccdaeb81f12f657b44b5a117b65d9d38e2 (diff)
downloadgit-cf606e3ddd8666b990a6560be77eb9f28af0e47d.tar.gz
git name-rev writes beyond the end of malloc() with large generations
When using git name-rev on my kernel tree I triggered a malloc() corruption warning from glibc. apw@pinky$ git log --pretty=one $N/base.. | git name-rev --stdin *** glibc detected *** malloc(): memory corruption: 0x0bff8950 *** Aborted This comes from name_rev() which is building the name of the revision in a malloc'd string, which it sprintf's into: char *new_name = xmalloc(len + 8); [...] sprintf(new_name, "%.*s~%d^%d", len, tip_name, generation, parent_number); This allocation is only sufficient if the generation number is less than 5 digits, in my case generation was 13432. In reality parent_number can be up to 16 so that also can require two digits, reducing us to 3 digits before we are at risk of blowing this allocation. This patch introduces a decimal_length() which approximates the number of digits a type may hold, it produces the following: Type Longest Value Len Est ---- ------------- --- --- unsigned char 256 3 4 unsigned short 65536 5 6 unsigned long 4294967296 10 11 unsigned long long 18446744073709551616 20 21 char -128 4 4 short -32768 6 6 long -2147483648 11 11 long long -9223372036854775808 20 21 This is then used to size the new_name. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'builtin-name-rev.c')
-rw-r--r--builtin-name-rev.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/builtin-name-rev.c b/builtin-name-rev.c
index c022224361..ef16385907 100644
--- a/builtin-name-rev.c
+++ b/builtin-name-rev.c
@@ -58,7 +58,10 @@ copy_data:
parents = parents->next, parent_number++) {
if (parent_number > 1) {
int len = strlen(tip_name);
- char *new_name = xmalloc(len + 8);
+ char *new_name = xmalloc(len +
+ 1 + decimal_length(generation) + /* ~<n> */
+ 1 + 2 + /* ^NN */
+ 1);
if (len > 2 && !strcmp(tip_name + len - 2, "^0"))
len -= 2;