From 11486b5265b2e0e2cf8b140018c47bd9a35cba93 Mon Sep 17 00:00:00 2001 From: Paul Jakma Date: Thu, 28 Feb 2008 23:26:02 +0000 Subject: [lib] Fix the struct message LOOKUP function to be more robust 2008-02-28 Paul Jakma * log.c: (mes_lookup) Sowmini Varadhan diagnosed a problem where this function can cause a NULL dereference, on lookups for unknown indices, or messages with NULL strings. Can occur, e.g., debug logging code when processing received messages. Fixed to accept a pointer to a default string to be used if there is no match. * log.h: LOOKUP adjusted to match --- lib/log.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) (limited to 'lib/log.c') diff --git a/lib/log.c b/lib/log.c index ff47cae0..ce00bfbb 100644 --- a/lib/log.c +++ b/lib/log.c @@ -752,14 +752,24 @@ lookup (struct message *mes, int key) } /* Older/faster version of message lookup function, but requires caller to pass - in the array size (instead of relying on a 0 key to terminate the search). */ + * in the array size (instead of relying on a 0 key to terminate the search). + * + * The return value is the message string if found, or the 'none' pointer + * provided otherwise. + */ const char * -mes_lookup (struct message *meslist, int max, int index) +mes_lookup (struct message *meslist, int max, int index, const char *none) { + int pos = index - meslist[0].key; + /* first check for best case: index is in range and matches the key - value in that slot */ - if ((index >= 0) && (index < max) && (meslist[index].key == index)) - return meslist[index].str; + * value in that slot. + * NB: key numbering might be offset from 0. E.g. protocol constants + * often start at 1. + */ + if ((pos >= 0) && (pos < max) + && (meslist[pos].key == index)) + return meslist[pos].str; /* fall back to linear search */ { @@ -769,14 +779,17 @@ mes_lookup (struct message *meslist, int max, int index) { if (meslist->key == index) { + const char *str = (meslist->str ? meslist->str : none); + zlog_debug ("message index %d [%s] found in position %d (max is %d)", - index, meslist->str, i, max); - return meslist->str; + index, str, i, max); + return str; } } } zlog_err("message index %d not found (max is %d)", index, max); - return NULL; + assert (none); + return none; } /* Wrapper around strerror to handle case where it returns NULL. */ -- cgit v1.2.1