From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591488; b=BvFtUTOl9lCteVBdDGPImS1Nar3t172X1sucNAy3HoehPnABZtYpkgwvOKeHLvPU0rbJ p6zQN8D4eDwHSJEqrdq51mDJOQyKHa2CsVX0nvvGEYUTWoy9exWs7rtaIlBgbI49JevA5 Td82Vu6Bw7PmNppS1M/0WDzgDEC9Umtpc/w+FSt7KeTtK0Sm6cFo8KgcIpu4soVORSg6F ZYuVCFyNxF4OOnqDJ1guPzP8J7mhP2zW2fkmdeSFXr9wq/NgA/WPTViHYbDLtrYpcr6CV oGvVTl/LFfW3k34BT4un/dOvPShHHZBpi3po0I440pUE4zgqr8Sfc6PlwcAUtCINrLA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591488; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=rqHEufQAwFKuXMuNe4wkMi6WB5nTLz5LI9+LmWCg26Q=; b=k4Cl6TcG8kppXk+cF3jyReMWN+PrdT2B0TB2QiAudr8mHSciwGQZPQK1Y8pj+AdJeIrq 3mEJZaI+DTzjWPY34Ug6fY9a84rerD56A5/bYUe647JeRmyYnM7fGlzc1YdMQBo+crXdO BfHs/+Om8e/eu58Ja1ExzKaoZ2O9viBsKK1E+x6fk5vYN652AuAsDMmJYjWBZcho1GU5r Vh90wL1sJPCOXC+2/J9sFgD5xlsXKD5ZTLVrCoaVDsiauquwKfeLkvydXSFzbA4e4k3mm 9netdeaCcC3NhqwazZmevKArDcc9L7dXPIqwfxBGyk5kep0m1Bdn/pl+0UH692dXE+A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=EF4XA0A6; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F8CE607E059; Fri, 13 Nov 2026 17:38:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=EF4XA0A6 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFAAE1F000C7; Fri, 13 Nov 2026 17:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591488; bh=rqHEufQAwFKuXMuNe4wkMi6WB5nTLz5LI9+LmWCg26Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EF4XA0A6JC9pGRiUHeUQqgp798iNJ4B36xezt3OvkrGdPTQp/Zfn8BJAv5XYLDFUM 5x9ffyxJGnbo2K4ppw+/o9faKJNAFRhc3/isca1MtKSC8VBkZ7lkx4N1yP5EVlMBnT FyodNlMcDlrYNKCjKvkL4vN7Nzc9F3tRKazZEKXk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Kaixuan Li , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12 570/670] f2fs: bound the SIT/NAT bitmaps by the checkpoint pack Date: Fri, 13 Nov 2026 10:52:14 -0500 Message-ID: <20261113153831.178126719@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kaixuan Li [ Upstream commit 080833a32fd5dc10b3acf2fa9af9b3213e6cb617 ] sit_ver_bitmap_bytesize and nat_ver_bitmap_bytesize are used as memcpy lengths into and out of sbi->ckpt, which is sized from cp_payload alone, and nothing compares either length against that allocation. sanity_check_ckpt() has checked these two fields since c77ec61ca0a4, which added them after a crafted image overran build_sit_info(). That check ties each length to a segment count; it never compares either against the allocation, which is the half this adds. Mounting over-reads in build_sit_info() and build_node_manager(), and the first checkpoint writes the same lengths back through the same pointers, so the over-read's contents reach the on-disk checkpoint. An unmount is enough; the filesystem does not have to be used. Bound both ends the way __bitmap_ptr() lays them out. The three branches differ, so a single sum of the two lengths would still admit a small overflow when cp_payload is non-zero. Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure") Cc: stable@kernel.org Signed-off-by: Kaixuan Li Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim [ sashal: Replaced both F2FS_BLKSIZE(sbi) uses with the F2FS_BLKSIZE constant. ] Signed-off-by: Sasha Levin --- fs/f2fs/super.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 31724ab224d4a..ec3e20cd6c5eb 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3773,6 +3773,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi) block_t avail_node_count, valid_node_count; unsigned int nat_blocks, nat_bits_bytes, nat_bits_blocks; unsigned int sit_blk_cnt; + unsigned long long ckpt_size, sit_end, nat_end; int i, j; total = le32_to_cpu(raw_super->segment_count); @@ -3904,6 +3905,29 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi) return 1; } + /* + * Nothing above ties the bitmap lengths to sbi->ckpt, which is + * (1 + cp_payload) blocks. Bound both ends the way __bitmap_ptr() + * lays them out. + */ + ckpt_size = (unsigned long long)(cp_payload + 1) * F2FS_BLKSIZE; + if (__is_set_ckpt_flags(ckpt, CP_LARGE_NAT_BITMAP_FLAG)) { + nat_end = CP_MIN_CHKSUM_OFFSET + sizeof(__le32) + nat_bitmap_size; + sit_end = nat_end + sit_bitmap_size; + } else if (cp_payload > 0) { + nat_end = CP_MIN_CHKSUM_OFFSET + nat_bitmap_size; + sit_end = F2FS_BLKSIZE + sit_bitmap_size; + } else { + sit_end = CP_MIN_CHKSUM_OFFSET + sit_bitmap_size; + nat_end = sit_end + nat_bitmap_size; + } + + if (sit_end > ckpt_size || nat_end > ckpt_size) { + f2fs_err(sbi, "Bitmaps do not fit the checkpoint pack: sit ends at %llu, nat at %llu, pack is %llu bytes", + sit_end, nat_end, ckpt_size); + return 1; + } + if (__is_set_ckpt_flags(ckpt, CP_LARGE_NAT_BITMAP_FLAG) && le32_to_cpu(ckpt->checksum_offset) != CP_MIN_CHKSUM_OFFSET) { f2fs_warn(sbi, "using deprecated layout of large_nat_bitmap, " -- 2.53.0