RecordFlushReplyBuffer can call itself recursively through
WriteClient->CallCallbacks->_CallCallbacks->RecordFlushAllContexts
when the recording client's buffer cannot be completely emptied in one
WriteClient. When a such a recursion occurs, it will not be broken out
of which results in segmentation fault when the stack is exhausted.
This patch adds a counter (a flag, really) that guards against this
situation, to break out of the recursion.
One alternative to this change would be to change _CallCallbacks to
check the corresponding counter before the callback loop, but that
might affect existing behavior, which may be relied upon.
Reviewed-by: Rami Ylimäki <rami.ylim...@vincit.fi>
Signed-off-by: Erkki Seppälä <erkki.sepp...@vincit.fi>
---
record/record.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/record/record.c b/record/record.c
index 6a93d7a..bea3046 100644
--- a/record/record.c
+++ b/record/record.c
@@ -77,6 +77,7 @@ typedef struct {
char bufCategory; /* category of protocol in replyBuffer */
int numBufBytes; /* number of bytes in replyBuffer */
char replyBuffer[REPLY_BUF_SIZE]; /* buffered recorded protocol */
+ int inFlush; /* are we inside
RecordFlushReplyBuffer */
} RecordContextRec, *RecordContextPtr;
/* RecordMinorOpRec - to hold minor opcode selections for extension requests
@@ -245,8 +246,9 @@ RecordFlushReplyBuffer(
int len2
)
{
- if (!pContext->pRecordingClient || pContext->pRecordingClient->clientGone)
+ if (!pContext->pRecordingClient || pContext->pRecordingClient->clientGone
|| pContext->inFlush)
return;
+ ++pContext->inFlush;
if (pContext->numBufBytes)
WriteToClient(pContext->pRecordingClient, pContext->numBufBytes,
(char *)pContext->replyBuffer);
@@ -255,6 +257,7 @@ RecordFlushReplyBuffer(
WriteToClient(pContext->pRecordingClient, len1, (char *)data1);
if (len2)
WriteToClient(pContext->pRecordingClient, len2, (char *)data2);
+ --pContext->inFlush;
} /* RecordFlushReplyBuffer */
@@ -1938,6 +1941,7 @@ ProcRecordCreateContext(ClientPtr client)
pContext->numBufBytes = 0;
pContext->pBufClient = NULL;
pContext->continuedReply = 0;
+ pContext->inFlush = 0;
err = RecordRegisterClients(pContext, client,
(xRecordRegisterClientsReq *)stuff);
--
1.7.0.4
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