From: Konstantin Komarov Date: Mon, 1 Jun 2026 08:57:56 +0000 (+0200) Subject: fs/ntfs3: validate lcns_follow in log_replay conversion X-Git-Tag: v7.2-rc1~45^2~5 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6a4c53a2e26a865565bd6a460961e8d6fcb32329;p=thirdparty%2Flinux.git fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal") Cc: stable@vger.kernel.org Signed-off-by: Pavitra Jha [almaz.alexandrovich@paragon-software.com: fixed the conflicts] Signed-off-by: Konstantin Komarov --- diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c index 81a305d4bcf26..95e1cdb47475b 100644 --- a/fs/ntfs3/fslog.c +++ b/fs/ntfs3/fslog.c @@ -4257,13 +4257,26 @@ check_dirty_page_table: if (rst->major_ver) goto end_conv_1; /* reduce tab pressure. */ + t16 = le16_to_cpu(dptbl->size); + if (t16 < sizeof(struct DIR_PAGE_ENTRY)) { + log->set_dirty = true; + goto out; + } + + t32 = (t16 - sizeof(struct DIR_PAGE_ENTRY)) / sizeof(u64); + dp = NULL; while ((dp = enum_rstbl(dptbl, dp))) { struct DIR_PAGE_ENTRY_32 *dp0 = (struct DIR_PAGE_ENTRY_32 *)dp; - // NOTE: Danger. Check for of boundary. + u32 lcns = le32_to_cpu(dp->lcns_follow); + + if (lcns > t32) { + log->set_dirty = true; + goto out; + } + memmove(&dp->vcn, &dp0->vcn_low, - 2 * sizeof(u64) + - le32_to_cpu(dp->lcns_follow) * sizeof(u64)); + 2 * sizeof(u64) + lcns * sizeof(u64)); } end_conv_1: