From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2178) id 63B6A384641E; Thu, 25 Apr 2024 13:32:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 63B6A384641E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1714051951; bh=bBV3v62ph5/9saZvjjnb2LENRhC2FojN0UMhf/A1Ux8=; h=From:To:Subject:Date:From; b=JGupn72/caAwMSVZtd5VqRyjAHaxehlcs+IsPBX3J9ZtY6PTDgIOWsI1mDg9pEEKp pjo7c2KAx6F0SsR9DOz/VQvggBRA0QlIHi1Zl096MsuVkGJ3v29wsMUw4t5/pLXIN9 3PgMaKN0iEIcoId6HEmy5Cu+cwyIO8Uf4O6YRMjY= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Florian Weimer To: glibc-cvs@sourceware.org Subject: [glibc] CVE-2024-33600: nscd: Avoid null pointer crashes after notfound response (bug 31678) X-Act-Checkin: glibc X-Git-Author: Florian Weimer X-Git-Refname: refs/heads/master X-Git-Oldrev: 7835b00dbce53c3c87bbbb1754a95fb5e58187aa X-Git-Newrev: b048a482f088e53144d26a61c390bed0210f49f2 Message-Id: <20240425133231.63B6A384641E@sourceware.org> Date: Thu, 25 Apr 2024 13:32:29 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b048a482f088e53144d26a61c390bed0210f49f2 commit b048a482f088e53144d26a61c390bed0210f49f2 Author: Florian Weimer Date: Thu Apr 25 15:01:07 2024 +0200 CVE-2024-33600: nscd: Avoid null pointer crashes after notfound response (bug 31678) The addgetnetgrentX call in addinnetgrX may have failed to produce a result, so the result variable in addinnetgrX can be NULL. Use db->negtimeout as the fallback value if there is no result data; the timeout is also overwritten below. Also avoid sending a second not-found response. (The client disconnects after receiving the first response, so the data stream did not go out of sync even without this fix.) It is still beneficial to add the negative response to the mapping, so that the client can get it from there in the future, instead of going through the socket. Reviewed-by: Siddhesh Poyarekar Diff: --- nscd/netgroupcache.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c index c18fe111f3..e22ffa5884 100644 --- a/nscd/netgroupcache.c +++ b/nscd/netgroupcache.c @@ -511,14 +511,15 @@ addinnetgrX (struct database_dyn *db, int fd, request_header *req, datahead_init_pos (&dataset->head, sizeof (*dataset) + req->key_len, sizeof (innetgroup_response_header), - he == NULL ? 0 : dh->nreloads + 1, result->head.ttl); + he == NULL ? 0 : dh->nreloads + 1, + result == NULL ? db->negtimeout : result->head.ttl); /* Set the notfound status and timeout based on the result from getnetgrent. */ - dataset->head.notfound = result->head.notfound; + dataset->head.notfound = result == NULL || result->head.notfound; dataset->head.timeout = timeout; dataset->resp.version = NSCD_VERSION; - dataset->resp.found = result->resp.found; + dataset->resp.found = result != NULL && result->resp.found; /* Until we find a matching entry the result is 0. */ dataset->resp.result = 0; @@ -566,7 +567,9 @@ addinnetgrX (struct database_dyn *db, int fd, request_header *req, goto out; } - if (he == NULL) + /* addgetnetgrentX may have already sent a notfound response. Do + not send another one. */ + if (he == NULL && dataset->resp.found) { /* We write the dataset before inserting it to the database since while inserting this thread might block and so would