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authorFlorian Weimer <fweimer@redhat.com>2024-04-25 15:01:07 +0200
committerFlorian Weimer <fweimer@redhat.com>2024-04-25 15:39:23 +0200
commit2ae9446c1b7a3064743b4a51c0bbae668ee43e4c (patch)
tree5316177e753b351aee616fbb4e2a20c3bb4d427f
parent541ea5172aa658c4bd5c6c6d6fd13903c3d5bb0a (diff)
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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 <siddhesh@sourceware.org> (cherry picked from commit b048a482f088e53144d26a61c390bed0210f49f2)
-rw-r--r--nscd/netgroupcache.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c
index 32c6aef3..c3cd79d 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