Messages in this thread | | | Subject | Re: [PATCH][next] cpumask: allocate enough space for string and trailing '\0' char | From | Paul Gortmaker <> | Date | Mon, 9 Nov 2020 23:57:15 -0500 |
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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.king@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.king@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")) { >
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