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Fix off-by-one error in Beast-format input.

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This would mangle messages if the first byte of a message ended up
as the last byte returned by a read() call - it would read beyond
the end of the buffer, decide the message was damaged, and then run
off into the message data looking for a new delimiter. Sometimes
that would work (only dropping one message), but sometimes it would
run into data that happened to look like a message start but
actually wasn't, and then try to interpret that, leading to completely
bogus message data being read.

Fixes #29.
This commit is contained in:
Oliver Jowett 2015-02-21 23:50:35 +00:00
parent 8e9220e330
commit e7d7fd549c
1 changed files with 1 additions and 1 deletions
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2
net_io.c
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@ -1328,7 +1328,7 @@ void modesReadFromClient(struct client *c, char *sep,
// in the buffer, note that we full-scan the buffer at every read for simplicity. // in the buffer, note that we full-scan the buffer at every read for simplicity.
left = c->buflen; // Length of valid search for memchr() left = c->buflen; // Length of valid search for memchr()
while (left && ((s = memchr(e, (char) 0x1a, left)) != NULL)) { // The first byte of buffer 'should' be 0x1a while (left > 1 && ((s = memchr(e, (char) 0x1a, left)) != NULL)) { // The first byte of buffer 'should' be 0x1a
s++; // skip the 0x1a s++; // skip the 0x1a
if (*s == '1') { if (*s == '1') {
e = s + MODEAC_MSG_BYTES + 8; // point past remainder of message e = s + MODEAC_MSG_BYTES + 8; // point past remainder of message