Hello,
This patch fixes a buffer overflow in TCP requests. Since the read is not
actually being retried, the byte written by the child can be left in the pipe.
When that happens, cache_recv_insert() reads the length of the name, which is
now multiplied by 256 due to the extra 0 byte (8 bit shift) and results in
daemon->namebuff being overflowed. Namebuff is immediately before the daemon
struct in memory so it ends up corrupting the beginning of the daemon struct.
diff --git a/src/dnsmasq.c b/src/dnsmasq.c
index 6481de8..457dea3 100644
--- a/src/dnsmasq.c
+++ b/src/dnsmasq.c
@@ -1887,7 +1887,7 @@ static void check_dns_listeners(time_t now)
single byte comes back up the pipe, which
is sent by the child after it has closed the
netlink socket. */
- retry_send(read(pipefd[0], &a, 1));
+ while (retry_send(read(pipefd[0], &a, 1)));
#endif
break;
}
@@ -1928,7 +1928,7 @@ static void check_dns_listeners(time_t now)
#ifdef HAVE_LINUX_NETWORK
/* See comment above re netlink socket. */
close(daemon->netlinkfd);
- retry_send(write(pipefd[1], &a, 1));
+ while (retry_send(write(pipefd[1], &a, 1)));
#endif
}
Frank
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