From cbbc8d67301c650dd683566d44ff554993556224 Mon Sep 17 00:00:00 2001 From: Ed Maste Date: Wed, 17 Jul 2024 10:33:53 -0400 Subject: [PATCH] pipe: keep uio_iovcnt consistent In pipe_build_write_buffer we increment uio_iov but did not update uio_iovcnt. This would not cause an OOB read (thanks to to uio_resid) but is inconsistent and could be an issue if other code changes are made in the future. Reported by: Synacktiv Reviewed by: jhb, markj, brooks Sponsored by: The Alpha-Omega Project Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D45999 (cherry picked from commit d8ff42e816848a0d4a427755b46b8560cb86ebc8) --- sys/kern/sys_pipe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c index 1c8d72f70a9..4c6f010a03f 100644 --- a/sys/kern/sys_pipe.c +++ b/sys/kern/sys_pipe.c @@ -942,8 +942,10 @@ pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio) uio->uio_iov->iov_len -= size; uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; - if (uio->uio_iov->iov_len == 0) + if (uio->uio_iov->iov_len == 0) { uio->uio_iov++; + uio->uio_iovcnt--; + } uio->uio_resid -= size; uio->uio_offset += size; return (0);