Date: Sun, 18 Jul 2021 00:36:54 GMT From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: d2c8c4d15a6e - stable/13 - LinuxKPI: fix sg_pcopy_from_buffer() Message-ID: <202107180036.16I0ass2049738@gitrepo.freebsd.org>
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The branch stable/13 has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=d2c8c4d15a6e65657b52b058b38d609e65202ad4 commit d2c8c4d15a6e65657b52b058b38d609e65202ad4 Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2021-06-07 15:00:19 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2021-07-18 00:35:04 +0000 LinuxKPI: fix sg_pcopy_from_buffer() In sg_pcopy_from_buffer() is an error in that skip can underflow and lead to bogus page arithmetics which may lead to memory corruption or more likely panics. Once we found a s/g page to copy into there is nothing to skip anymore so simply set skip to 0. Sponsored by: The FreeBSD Foundation Reviewed by: hselasky Differential Revision: https://reviews.freebsd.org/D30676 (cherry picked from commit edfcdffefc1671b7688c8806ae1f59484954dcc7) --- sys/compat/linuxkpi/common/include/linux/scatterlist.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sys/compat/linuxkpi/common/include/linux/scatterlist.h b/sys/compat/linuxkpi/common/include/linux/scatterlist.h index ebf0632f6f58..5e42876facd0 100644 --- a/sys/compat/linuxkpi/common/include/linux/scatterlist.h +++ b/sys/compat/linuxkpi/common/include/linux/scatterlist.h @@ -520,12 +520,13 @@ sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, memcpy(p, b, len); sf_buf_free(sf); + /* We copied so nothing more to skip. */ + skip = 0; copied += len; /* Either we exactly filled the page, or we are done. */ buflen -= len; if (buflen == 0) break; - skip -= len; b += len; } sched_unpin();
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