From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A64C423EB5; Thu, 16 Jul 2026 14:20:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211613; cv=none; b=P2wFFQPe1DmgqwRgsIbhvL1Wf2UV5mNwSIU4rpyL2LFy9ftzKmDtkX4lAmDYE8pMkJi7hBI4a1JMpP7lSzABJOKu/hO4pZYO+2K8t2QB+QG59QFKJpTnQ1IXjIwTdYf7qzw7npNGjSy0nugaESWIaJ1e0TZwvp3+yPnlMfar8sg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211613; c=relaxed/simple; bh=0Jl0Blz4MbLEiKNWbHCcU4XeYuibURNjG7Tz3PImBfM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iN+bkt5IAsPfmu0DhzXK7zfiNra2F0o0FLJ0tTynmDp1Q7lXbmdUWjNNQiX1tukaNn9QDm0zJ1tqtNUcEvKi2bCxOQ2p7HpJ0zLI2AuWUm5vaC+BBG4tr8NpNCfhp3jPz936Oqqfj4IXrRO/6HU9IpHg8bqJsxY8dJgeBT7nN/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kUIUXnJU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="kUIUXnJU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D2FC1F000E9; Thu, 16 Jul 2026 14:20:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784211611; bh=oM1hGrAu7Z6OrnXaxVeVmdmtmsD7JIumA6mRG6N+eRA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kUIUXnJUs/74WIaWhILbHUM138iLli+lzMWHQY6QOfFbcb6ShtDSGwqIZvG8cfpZ1 fSKVFHtfzOsL5XX9VqEEtmiQV5GEZ38FAQJEY/RuppIRT/R7rX2okrIc5IRJEd55Fe X0l2h5YOn+O1WbiFZe8kGLoU0PKtUVAjnHlZz47g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Daeho Jeong , Sunmin Jeong , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12 014/349] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode Date: Thu, 16 Jul 2026 15:29:08 +0200 Message-ID: <20260716133033.612895993@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133033.287196923@linuxfoundation.org> References: <20260716133033.287196923@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Yu [ Upstream commit e0288584baa5dc41df4a829a023c4c1b33fe53d7 ] - ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink - f2fs_gc - gc_data_segment - ra_data_block(cow_inode) - mapping = F2FS_I(inode)->atomic_inode->i_mapping : f2fs_is_cow_file(cow_inode) is true - f2fs_evict_inode(atomic_inode) - clear_inode_flag(fi->cow_inode, FI_COW_FILE) - F2FS_I(fi->cow_inode)->atomic_inode = NULL ... - truncate_inode_pages_final(atomic_inode) - f2fs_grab_cache_folio(mapping) : create folio in atomic_inode->mapping - clear_inode(atomic_inode) - BUG_ON(atomic_inode->i_data.nrpages) We need to add a reference on fi->atomic_inode before using its mapping field during garbage collection, otherwise, it will cause UAF issue. Cc: stable@kernel.org Cc: Daeho Jeong Cc: Sunmin Jeong Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") Fixes: f18d00769336 ("f2fs: use meta inode for GC of COW file") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/gc.c | 50 ++++++++++++++++++++++++++++++++++++++++++-------- fs/f2fs/inode.c | 11 ++++++++--- 2 files changed, 50 insertions(+), 11 deletions(-) --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1213,8 +1213,8 @@ static bool is_alive(struct f2fs_sb_info static int ra_data_block(struct inode *inode, pgoff_t index) { struct f2fs_sb_info *sbi = F2FS_I_SB(inode); - struct address_space *mapping = f2fs_is_cow_file(inode) ? - F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping; + struct address_space *mapping = inode->i_mapping; + struct inode *atomic_inode = NULL; struct dnode_of_data dn; struct page *page; struct f2fs_io_info fio = { @@ -1229,9 +1229,22 @@ static int ra_data_block(struct inode *i }; int err; + f2fs_down_read(&F2FS_I(inode)->i_sem); + if (f2fs_is_cow_file(inode)) { + atomic_inode = igrab(F2FS_I(inode)->atomic_inode); + if (!atomic_inode) { + f2fs_up_read(&F2FS_I(inode)->i_sem); + return -EBUSY; + } + mapping = atomic_inode->i_mapping; + } + f2fs_up_read(&F2FS_I(inode)->i_sem); + page = f2fs_grab_cache_page(mapping, index, true); - if (!page) - return -ENOMEM; + if (!page) { + err = -ENOMEM; + goto out_iput; + } if (f2fs_lookup_read_extent_cache_block(inode, index, &dn.data_blkaddr)) { @@ -1288,11 +1301,16 @@ got_it: f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE); f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE); + if (atomic_inode) + iput(atomic_inode); return 0; put_encrypted_page: f2fs_put_page(fio.encrypted_page, 1); put_page: f2fs_put_page(page, 1); +out_iput: + if (atomic_inode) + iput(atomic_inode); return err; } @@ -1303,8 +1321,8 @@ put_page: static int move_data_block(struct inode *inode, block_t bidx, int gc_type, unsigned int segno, int off) { - struct address_space *mapping = f2fs_is_cow_file(inode) ? - F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping; + struct address_space *mapping = inode->i_mapping; + struct inode *atomic_inode = NULL; struct f2fs_io_info fio = { .sbi = F2FS_I_SB(inode), .ino = inode->i_ino, @@ -1326,10 +1344,23 @@ static int move_data_block(struct inode (fio.sbi->gc_mode != GC_URGENT_HIGH) ? CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA; + f2fs_down_read(&F2FS_I(inode)->i_sem); + if (f2fs_is_cow_file(inode)) { + atomic_inode = igrab(F2FS_I(inode)->atomic_inode); + if (!atomic_inode) { + f2fs_up_read(&F2FS_I(inode)->i_sem); + return -EBUSY; + } + mapping = atomic_inode->i_mapping; + } + f2fs_up_read(&F2FS_I(inode)->i_sem); + /* do not read out */ page = f2fs_grab_cache_page(mapping, bidx, false); - if (!page) - return -ENOMEM; + if (!page) { + err = -ENOMEM; + goto out_iput; + } if (!check_valid_map(F2FS_I_SB(inode), segno, off)) { err = -ENOENT; @@ -1456,6 +1487,9 @@ put_out: f2fs_put_dnode(&dn); out: f2fs_put_page(page, 1); +out_iput: + if (atomic_inode) + iput(atomic_inode); return err; } --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -839,10 +839,15 @@ void f2fs_evict_inode(struct inode *inod f2fs_abort_atomic_write(inode, true); if (fi->cow_inode && f2fs_is_cow_file(fi->cow_inode)) { - clear_inode_flag(fi->cow_inode, FI_COW_FILE); - F2FS_I(fi->cow_inode)->atomic_inode = NULL; - iput(fi->cow_inode); + struct inode *cow_inode = fi->cow_inode; + + f2fs_down_write(&F2FS_I(cow_inode)->i_sem); + clear_inode_flag(cow_inode, FI_COW_FILE); + F2FS_I(cow_inode)->atomic_inode = NULL; fi->cow_inode = NULL; + f2fs_up_write(&F2FS_I(cow_inode)->i_sem); + + iput(cow_inode); } trace_f2fs_evict_inode(inode);