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 06F773D953A for ; Fri, 3 Jul 2026 13:31:09 +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=1783085472; cv=none; b=uwp4BwGgNx95VBE5a1afj70btw7tMtZhGpWMhc1hAtQkv6YX5aP2tzq1R6xWgNvU1/dco3FOhKwTh8jDKkKKix4JdpQazMGZ83M/oyN5i566v9wd+TlLTqXm9RUA5wa/Wv97RsR+vmRvbePEl6fORhKB+e8cWQVawOEbDAc6W7g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783085472; c=relaxed/simple; bh=JGXScCGR/di1wN3+WrnxQlTdSeITPuH+DPhBODnBL7I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=h5VhZIoWePFzolkBhuT7N+UNknE8ZcQpM8EEvd8HV/qAwEMJMGjdZ/0xKCnITefVOJvsoO4mNYysbM02XETFQbG3C4xoCP7q51ssmu+elefzJnfH9u+XzmTjGu4I6gISJoAlw5mXwCt+o1ou3kYgk737wBOIsYns43LqOC6LM+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Rnldnqgy; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rnldnqgy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A81B61F00A3A; Fri, 3 Jul 2026 13:31:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783085468; bh=cHo8D9lpmhGiBjRS93yYrKGR+wPZJvsnx7ZJZ+67+SI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RnldnqgyZ9B3DAauwvVWGx6NYdR3bwHCBYrNKskol1ayXP27zSoJNF2aIJZQ/mBcm U5PIQr1TBDsjUxY5tisx0YrtknEFLF+rOrRO175w3kSN5pvjTfZyqjiWx/UKfvdM4I mxpkFGYABhDf0xrMEs6sED0PhTfyDB1yh7KinTG87AFATD1qgdnylujDIyjw5jNupX in6uRJLevZufKT2jCVytGv+ALFOz9KtkHgTiblty1reJBYSbgIl6SAPI67UfFfHAGn Hg7ulaQjtiXkhXuzXsKdO4JGGNOnrlP8Je2X1XRHF2ExpzKmsgxCjdhxN2FxlBElSH sbaahceOiVemQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Chao Yu , stable@kernel.org, Daeho Jeong , Sunmin Jeong , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.6.y] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode Date: Fri, 3 Jul 2026 09:31:04 -0400 Message-ID: <20260703133105.4123725-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026070242-unbridle-scallop-a9c6@gregkh> References: <2026070242-unbridle-scallop-a9c6@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- fs/f2fs/gc.c | 50 +++++++++++++++++++++++++++++++++++++++++-------- fs/f2fs/inode.c | 11 ++++++++--- 2 files changed, 50 insertions(+), 11 deletions(-) diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 5654608a119235..ac21950f53cd27 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1173,8 +1173,8 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, 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 = { @@ -1189,9 +1189,22 @@ static int ra_data_block(struct inode *inode, pgoff_t index) }; 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)) { @@ -1250,11 +1263,16 @@ static int ra_data_block(struct inode *inode, pgoff_t index) 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; } @@ -1265,8 +1283,8 @@ static int ra_data_block(struct inode *inode, pgoff_t index) 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, @@ -1288,10 +1306,23 @@ static int move_data_block(struct inode *inode, block_t bidx, (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; @@ -1413,6 +1444,9 @@ static int move_data_block(struct inode *inode, block_t bidx, f2fs_put_dnode(&dn); out: f2fs_put_page(page, 1); +out_iput: + if (atomic_inode) + iput(atomic_inode); return err; } diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index db80b6cad325cf..354960b1ae958c 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -837,10 +837,15 @@ void f2fs_evict_inode(struct inode *inode) 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); -- 2.53.0