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tracing: Fix parsing of globs with a wildcard at the beginning 

commit 0723402141 upstream.

Al Viro reported:

    For substring - sure, but what about something like "*a*b" and "a*b"?
    AFAICS, filter_parse_regex() ends up with identical results in both
    cases - MATCH_GLOB and *search = "a*b".  And no way for the caller
    to tell one from another.

Testing this with the following:

 # cd /sys/kernel/tracing
 # echo '*raw*lock' > set_ftrace_filter
 bash: echo: write error: Invalid argument

With this patch:

 # echo '*raw*lock' > set_ftrace_filter
 # cat set_ftrace_filter
_raw_read_trylock
_raw_write_trylock
_raw_read_unlock
_raw_spin_unlock
_raw_write_unlock
_raw_spin_trylock
_raw_spin_lock
_raw_write_lock
_raw_read_lock

Al recommended not setting the search buffer to skip the first '*' unless we
know we are not using MATCH_GLOB. This implements his suggested logic.

Link: http://lkml.kernel.org/r/20180127170748.GF13338@ZenIV.linux.org.uk

Cc: stable@vger.kernel.org
Fixes: 60f1d5e3ba ("ftrace: Support full glob matching")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Suggsted-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Steven Rostedt (VMware) 2018-02-05 22:18:11 -05:00 committed by Greg Kroah-Hartman
parent 29b4af7040
commit 2949758414
1 changed files with 4 additions and 5 deletions
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9
kernel/trace/trace_events_filter.c
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@ -400,7 +400,6 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
for (i = 0; i < len; i++) {
if (buff[i] == '*') {
if (!i) {
*search = buff + 1;
type = MATCH_END_ONLY;
} else if (i == len - 1) {
if (type == MATCH_END_ONLY)
@ -410,14 +409,14 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
buff[i] = 0;
break;
} else { /* pattern continues, use full glob */
type = MATCH_GLOB;
break;
return MATCH_GLOB;
}
} else if (strchr("[?\\", buff[i])) {
type = MATCH_GLOB;
break;
return MATCH_GLOB;
}
}
if (buff[0] == '*')
*search = buff + 1;
return type;
}