From: Antonio Quartulli Date: Sat, 6 Jan 2018 18:31:49 +0000 (+0800) Subject: ss: fix crash when skipping disabled header field X-Git-Tag: v4.15.0~39 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=192be8fccbdd752f37afc31ee0fa806a662bb9dd;p=thirdparty%2Fiproute2.git ss: fix crash when skipping disabled header field When the first header field is disabled (i.e. when passing the -t option), field_flush() is invoked with the `buffer` global variable still zero'd. However, in field_flush() we try to access buffer.cur->len during variables initialization, thus leading to a SIGSEGV. It's interesting to note that this bug appears only when the code is compiled with -O0, because the compiler is smart enough to immediately jump to the return statement if optimizations are enabled and skip the faulty instruction. Cc: Stefano Brivio Cc: Stephen Hemminger Signed-off-by: Antonio Quartulli Signed-off-by: Stephen Hemminger --- diff --git a/misc/ss.c b/misc/ss.c index 1abf43d08..b35859dc4 100644 --- a/misc/ss.c +++ b/misc/ss.c @@ -1018,12 +1018,15 @@ static void print_right_spacing(struct column *f, int printed) /* Done with field: update buffer pointer, start new token after current one */ static void field_flush(struct column *f) { - struct buf_chunk *chunk = buffer.tail; - unsigned int pad = buffer.cur->len % 2; + struct buf_chunk *chunk; + unsigned int pad; if (f->disabled) return; + chunk = buffer.tail; + pad = buffer.cur->len % 2; + if (buffer.cur->len > f->max_len) f->max_len = buffer.cur->len;