On 2020-11-09 8:07 p.m., Qian Cai wrote:
On Mon, 2020-11-09 at 13:04 +0000, Colin King wrote:
From: Colin Ian King <colin.k...@canonical.com>
Currently the allocation of cpulist is based on the length of buf but does
not include the addition end of string '\0' terminator. Static analysis is
reporting this as a potential out-of-bounds access on cpulist. Fix this by
allocating enough space for the additional '\0' terminator.
Addresses-Coverity: ("Out-of-bounds access")
Fixes: 65987e67f7ff ("cpumask: add "last" alias for cpu list specifications")
Yeah, this bad commit also introduced KASAN errors everywhere and then will
disable lockdep that makes our linux-next CI miserable. Confirmed that this
patch will fix it.
I appreciate the reports reminding me why I hate touching string handling.
But let us not lose sight of why linux-next exists. We want to
encourage code to appear there as a sounding board before it goes
mainline, so we can fix things and not pollute mainline git history
with those trivialities.
If you've decided to internalize linux-next as part of your CI, then
great, but do note that does not elevate linux-next to some pristine
status for the world at large. That only means you have to watch more
closely what is going on.
If you want to declare linux-next unbreakable -- well that would scare
away others to get the multi-arch or multi-config coverage that they may
not be able to do themselves. We are not going to do that.
I have (hopefully) fixed the "bad commit" in v2 -- as part of the
implicit linux-next rule "you broke it, you better fix it ASAP".
But "bad" and "miserable" can be things that might scare people off of
making use of linux-next for what it is meant to be for. And I am not
OK with that.
Thanks,
Paul.
--
Signed-off-by: Colin Ian King <colin.k...@canonical.com>
---
lib/cpumask.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 34ecb3005941..cb8a3ef0e73e 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -185,7 +185,7 @@ int __ref cpulist_parse(const char *buf, struct cpumask
*dstp)
{
int r;
char *cpulist, last_cpu[5]; /* NR_CPUS <= 9999 */
- size_t len = strlen(buf);
+ size_t len = strlen(buf) + 1;
bool early = !slab_is_available();
if (!strcmp(buf, "all")) {