54 lines
2.3 KiB
Diff
54 lines
2.3 KiB
Diff
commit b048a482f088e53144d26a61c390bed0210f49f2
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Thu Apr 25 15:01:07 2024 +0200
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CVE-2024-33600: nscd: Avoid null pointer crashes after notfound response (bug 31678)
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The addgetnetgrentX call in addinnetgrX may have failed to produce
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a result, so the result variable in addinnetgrX can be NULL.
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Use db->negtimeout as the fallback value if there is no result data;
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the timeout is also overwritten below.
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Also avoid sending a second not-found response. (The client
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disconnects after receiving the first response, so the data stream did
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not go out of sync even without this fix.) It is still beneficial to
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add the negative response to the mapping, so that the client can get
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it from there in the future, instead of going through the socket.
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Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c
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index c18fe111f3..e22ffa5884 100644
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--- a/nscd/netgroupcache.c
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+++ b/nscd/netgroupcache.c
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@@ -511,14 +511,15 @@ addinnetgrX (struct database_dyn *db, int fd, request_header *req,
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datahead_init_pos (&dataset->head, sizeof (*dataset) + req->key_len,
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sizeof (innetgroup_response_header),
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- he == NULL ? 0 : dh->nreloads + 1, result->head.ttl);
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+ he == NULL ? 0 : dh->nreloads + 1,
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+ result == NULL ? db->negtimeout : result->head.ttl);
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/* Set the notfound status and timeout based on the result from
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getnetgrent. */
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- dataset->head.notfound = result->head.notfound;
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+ dataset->head.notfound = result == NULL || result->head.notfound;
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dataset->head.timeout = timeout;
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dataset->resp.version = NSCD_VERSION;
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- dataset->resp.found = result->resp.found;
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+ dataset->resp.found = result != NULL && result->resp.found;
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/* Until we find a matching entry the result is 0. */
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dataset->resp.result = 0;
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@@ -566,7 +567,9 @@ addinnetgrX (struct database_dyn *db, int fd, request_header *req,
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goto out;
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}
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- if (he == NULL)
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+ /* addgetnetgrentX may have already sent a notfound response. Do
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+ not send another one. */
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+ if (he == NULL && dataset->resp.found)
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{
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/* We write the dataset before inserting it to the database
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since while inserting this thread might block and so would
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