From: Mikulas Patocka <mpatocka@redhat.com> stable inclusion from stable-v4.19.276 commit 98e311be44dbe31ad9c42aa067b2359bac451fda category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13114 CVE: CVE-2023-54317 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit f50714b57aecb6b3dc81d578e295f86d9c73f078 upstream. When we need to zero some range on a block device, the function __blkdev_issue_zero_pages submits a write bio with the bio vector pointing to the zero page. If we use dm-flakey with corrupt bio writes option, it will corrupt the content of the zero page which results in crashes of various userspace programs. Glibc assumes that memory returned by mmap is zeroed and it uses it for calloc implementation; if the newly mapped memory is not zeroed, calloc will return non-zeroed memory. Fix this bug by testing if the page is equal to ZERO_PAGE(0) and avoiding the corruption in this case. Cc: stable@vger.kernel.org Fixes: a00f5276e266 ("dm flakey: Properly corrupt multi-page bios.") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yuan can <yuancan@huawei.com> --- drivers/md/dm-flakey.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c index 9a955b8cf378..6a8c7ec21219 100644 --- a/drivers/md/dm-flakey.c +++ b/drivers/md/dm-flakey.c @@ -299,12 +299,15 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) * Overwrite the Nth byte of the bio's data, on whichever page * it falls. */ bio_for_each_segment(bvec, bio, iter) { if (bio_iter_len(bio, iter) > corrupt_bio_byte) { - char *segment = (page_address(bio_iter_page(bio, iter)) - + bio_iter_offset(bio, iter)); + char *segment; + struct page *page = bio_iter_page(bio, iter); + if (unlikely(page == ZERO_PAGE(0))) + break; + segment = (page_address(page) + bio_iter_offset(bio, iter)); segment[corrupt_bio_byte] = fc->corrupt_bio_value; DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " "(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n", bio, fc->corrupt_bio_value, fc->corrupt_bio_byte, (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf, -- 2.34.1