Fix possible overflow of the buffer used for expanding environment
variables when building file list.
$ cat usr/crash.list
file foo ${BIG}${BIG}${BIG}${BIG}${BIG}${BIG} 0755 0 0
$ BIG=$(perl -e 'print "A" x 4096;') ./usr/gen_init_cpio usr/crash.list
*** buffer overflow detected ***: ./usr/gen_init_cpio terminated
This also replaces the space-indenting with tabs.
Patch based on existing fix extracted from grsecurity.
Cc: Michal Marek <mma...@suse.cz>
Cc: Gene Sally <gene.sa...@timesys.com>
Cc: Brad Spengler <spen...@grsecurity.net>
Cc: PaX Team <pagee...@freemail.hu>
Cc: sta...@vger.kernel.org
Signed-off-by: Kees Cook <keesc...@chromium.org>
---
usr/gen_init_cpio.c | 43 +++++++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index af0f22f..aca6edc 100644
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -303,7 +303,7 @@ static int cpio_mkfile(const char *name, const char
*location,
int retval;
int rc = -1;
int namesize;
- int i;
+ unsigned int i;
mode |= S_IFREG;
@@ -381,25 +381,28 @@ error:
static char *cpio_replace_env(char *new_location)
{
- char expanded[PATH_MAX + 1];
- char env_var[PATH_MAX + 1];
- char *start;
- char *end;
-
- for (start = NULL; (start = strstr(new_location, "${")); ) {
- end = strchr(start, '}');
- if (start < end) {
- *env_var = *expanded = '\0';
- strncat(env_var, start + 2, end - start - 2);
- strncat(expanded, new_location, start - new_location);
- strncat(expanded, getenv(env_var), PATH_MAX);
- strncat(expanded, end + 1, PATH_MAX);
- strncpy(new_location, expanded, PATH_MAX);
- } else
- break;
- }
-
- return new_location;
+ char expanded[PATH_MAX + 1];
+ char env_var[PATH_MAX + 1];
+ char *start;
+ char *end;
+
+ for (start = NULL; (start = strstr(new_location, "${")); ) {
+ end = strchr(start, '}');
+ if (start < end) {
+ *env_var = *expanded = '\0';
+ strncat(env_var, start + 2, end - start - 2);
+ strncat(expanded, new_location, start - new_location);
+ strncat(expanded, getenv(env_var),
+ PATH_MAX - strlen(expanded));
+ strncat(expanded, end + 1,
+ PATH_MAX - strlen(expanded));
+ strncpy(new_location, expanded, PATH_MAX);
+ new_location[PATH_MAX] = 0;
+ } else
+ break;
+ }
+
+ return new_location;
}
--
1.7.9.5
--
Kees Cook
Chrome OS Security
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
