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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2018-05-09 11:59:32 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-16 10:06:51 +0200
commit4cc56b7a9db913c19206401390215703f66cbd2d (patch)
tree7258335ecf249c14075fb7cddffcbc720b074367 /kernel/trace
parentf307956cade0239d1436bb3eaffbc65ab3c5d767 (diff)
tracing: Fix regex_match_front() to not over compare the test string
commit dc432c3d7f9bceb3de6f5b44fb9c657c9810ed6d upstream. The regex match function regex_match_front() in the tracing filter logic, was fixed to test just the pattern length from testing the entire test string. That is, it went from strncmp(str, r->pattern, len) to strcmp(str, r->pattern, r->len). The issue is that str is not guaranteed to be nul terminated, and if r->len is greater than the length of str, it can access more memory than is allocated. The solution is to add a simple test if (len < r->len) return 0. Cc: stable@vger.kernel.org Fixes: 285caad415f45 ("tracing/filters: Fix MATCH_FRONT_ONLY filter matching") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_events_filter.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index f0e5408499b6..1ab2db6c127b 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -322,6 +322,9 @@ static int regex_match_full(char *str, struct regex *r, int len)
static int regex_match_front(char *str, struct regex *r, int len)
{
+ if (len < r->len)
+ return 0;
+
if (strncmp(str, r->pattern, r->len) == 0)
return 1;
return 0;