lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 27 Apr 2018 15:58:09 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, syzbot+7c449856228b63ac951e@...kaller.appspotmail.com, Jiri Olsa <jolsa@...nel.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Andi Kleen <andi@...stfloor.org>, "H. Peter Anvin" <hpa@...or.com>, Namhyung Kim <namhyung@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, syzkaller-bugs@...glegroups.com, x86@...nel.org, Arnaldo Carvalho de Melo <acme@...hat.com> Subject: [PATCH 4.9 19/74] perf: Fix sample_max_stack maximum check 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Olsa <jolsa@...nel.org> commit 5af44ca53d019de47efe6dbc4003dd518e5197ed upstream. The syzbot hit KASAN bug in perf_callchain_store having the entry stored behind the allocated bounds [1]. We miss the sample_max_stack check for the initial event that allocates callchain buffers. This missing check allows to create an event with sample_max_stack value bigger than the global sysctl maximum: # sysctl -a | grep perf_event_max_stack kernel.perf_event_max_stack = 127 # perf record -vv -C 1 -e cycles/max-stack=256/ kill ... perf_event_attr: size 112 ... sample_max_stack 256 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 4 Note the '-C 1', which forces perf record to create just single event. Otherwise it opens event for every cpu, then the sample_max_stack check fails on the second event and all's fine. The fix is to run the sample_max_stack check also for the first event with callchains. [1] https://marc.info/?l=linux-kernel&m=152352732920874&w=2 Reported-by: syzbot+7c449856228b63ac951e@...kaller.appspotmail.com Signed-off-by: Jiri Olsa <jolsa@...nel.org> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com> Cc: Andi Kleen <andi@...stfloor.org> Cc: H. Peter Anvin <hpa@...or.com> Cc: Namhyung Kim <namhyung@...nel.org> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Thomas Gleixner <tglx@...utronix.de> Cc: syzkaller-bugs@...glegroups.com Cc: x86@...nel.org Fixes: 97c79a38cd45 ("perf core: Per event callchain limit") Link: http://lkml.kernel.org/r/20180415092352.12403-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- kernel/events/callchain.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -117,19 +117,22 @@ int get_callchain_buffers(int event_max_ goto exit; } + /* + * If requesting per event more than the global cap, + * return a different error to help userspace figure + * this out. + * + * And also do it here so that we have &callchain_mutex held. + */ + if (event_max_stack > sysctl_perf_event_max_stack) { + err = -EOVERFLOW; + goto exit; + } + if (count > 1) { /* If the allocation failed, give up */ if (!callchain_cpus_entries) err = -ENOMEM; - /* - * If requesting per event more than the global cap, - * return a different error to help userspace figure - * this out. - * - * And also do it here so that we have &callchain_mutex held. - */ - if (event_max_stack > sysctl_perf_event_max_stack) - err = -EOVERFLOW; goto exit; }
Powered by blists - more mailing lists