Date: Mon, 6 Dec 2021 14:04:58 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 3f1756dabfe2 - stable/13 - dummynet: Avoid an out-of-bounds read in do_config() Message-ID: <202112061404.1B6E4wCo081797@gitrepo.freebsd.org>
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The branch stable/13 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=3f1756dabfe263c279c7dc29c54398d95f8b0988 commit 3f1756dabfe263c279c7dc29c54398d95f8b0988 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2021-11-29 18:50:21 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2021-12-06 14:04:19 +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 Sponsored by: The FreeBSD Foundation (cherry picked from commit d5ea04ee7ba6c7cd8e0918a080caf5f2c8fb3955) --- 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 d3242fd85817..cee478a03274 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;
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