git: d5ea04ee7ba6 - main - dummynet: Avoid an out-of-bounds read in do_config()
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Date: Mon, 29 Nov 2021 18:57:52 UTC
The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=d5ea04ee7ba6c7cd8e0918a080caf5f2c8fb3955 commit d5ea04ee7ba6c7cd8e0918a080caf5f2c8fb3955 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2021-11-29 18:50:21 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2021-11-29 18:57:24 +0000 dummynet: Avoid an out-of-bounds read in do_config() do_config() processes a buffer of variable-length dummynet commands. The loop which processes this buffer loads the fixed-length header before checking whether there are any bytes left to read, so it performs a 4-byte read past the end of the buffer before terminating. Restructure the loop to avoid this. Reported by: Jenkins (KASAN job) Reviewed by: kp MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D33132 --- sys/netpfil/ipfw/ip_dummynet.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/netpfil/ipfw/ip_dummynet.c b/sys/netpfil/ipfw/ip_dummynet.c index a890507f7b31..919445ff71d0 100644 --- a/sys/netpfil/ipfw/ip_dummynet.c +++ b/sys/netpfil/ipfw/ip_dummynet.c @@ -2011,7 +2011,9 @@ do_config(void *p, int l) } arg = NULL; dn = NULL; - for (off = 0; l >= sizeof(o); memcpy(&o, (char *)p + off, sizeof(o))) { + off = 0; + while (l >= sizeof(o)) { + memcpy(&o, (char *)p + off, sizeof(o)); if (o.len < sizeof(o) || l < o.len) { D("bad len o.len %d len %d", o.len, l); err = EINVAL;