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 172593EDE5E for ; Thu, 2 Jul 2026 13:09:32 +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=1782997775; cv=none; b=RaU4D42yPM3JXXQ8PWK0PGevNc6G4Itp6dyi7m/8aVm6V37JBQlWjNT8tj8IW9VkReGKDQXOQTd7k+u0PKoz34RXaXexN1bJI42CokvJE9N+ZDLzfXLbB+fd6Wlk9pfIkjGkNl3arRwVj/XIyOyqdzAPjt0Oo4hqllnKUZVlQGA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782997775; c=relaxed/simple; bh=61l/Po+9brnqkodH34Viq0Dbb3GexMvksQ0sahrz590=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=hwRSPW4DG//sCoHyQmLa7i3e1xxXQ6gsNdiPf76w4rqWH+LyIBvWEysaSvdz5M1gY5vgUKLYjSeSfE2WpdRHn8sPafrrDJVCTudsbBk/r5cCE5jzhrX29An+qBLZCsyDzY5V1wlvpUPwuJczcjB5ohAA8iHQ2eZBLcOkvWEYK88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pUH4igMH; 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="pUH4igMH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 355D91F000E9; Thu, 2 Jul 2026 13:09:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1782997771; bh=OIRINI0942FizP9/qwBbLxSmREz+NdDyamdTLysiV9Y=; h=Subject:To:Cc:From:Date; b=pUH4igMHKaVig5MXhAcy00pIbG824Bt/W0XC4dH5/GU6pjGP1+1jxzA4BNdmQIclt wOlVV7Cc6i7Y/G8GmKdAOrQMYpyRfZ2I5JzqCs2140n+hMR3EpGUAS7e4c7w7S8sok PCR4pnVeLFp7KsnXQO4oyJk7w/NZJ5h1ON1Gb+XI= Subject: FAILED: patch "[PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode" failed to apply to 6.18-stable tree To: chao@kernel.org,daehojeong@google.com,jaegeuk@kernel.org,s_min.jeong@samsung.com Cc: From: Date: Thu, 02 Jul 2026 15:09:42 +0200 Message-ID: <2026070242-refusing-previous-82e3@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x e0288584baa5dc41df4a829a023c4c1b33fe53d7 # git commit -s git send-email --to '' --in-reply-to '2026070242-refusing-previous-82e3@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From e0288584baa5dc41df4a829a023c4c1b33fe53d7 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Thu, 21 May 2026 10:15:05 +0800 Subject: [PATCH] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode - 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 diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 99bc59889825..69e0a867219d 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1220,8 +1220,8 @@ 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 folio *folio, *efolio; struct f2fs_io_info fio = { @@ -1236,9 +1236,22 @@ static int ra_data_block(struct inode *inode, pgoff_t index) }; int err = 0; + 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); + folio = f2fs_grab_cache_folio(mapping, index, true); - if (IS_ERR(folio)) - return PTR_ERR(folio); + if (IS_ERR(folio)) { + err = PTR_ERR(folio); + goto out_iput; + } if (f2fs_lookup_read_extent_cache_block(inode, index, &dn.data_blkaddr)) { @@ -1299,11 +1312,16 @@ 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, true); put_folio: f2fs_folio_put(folio, true); +out_iput: + if (atomic_inode) + iput(atomic_inode); return err; } @@ -1314,8 +1332,8 @@ 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, @@ -1337,10 +1355,23 @@ 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 */ folio = f2fs_grab_cache_folio(mapping, bidx, false); - if (IS_ERR(folio)) - return PTR_ERR(folio); + if (IS_ERR(folio)) { + err = PTR_ERR(folio); + goto out_iput; + } if (!check_valid_map(F2FS_I_SB(inode), segno, off)) { err = -ENOENT; @@ -1473,6 +1504,9 @@ static int move_data_block(struct inode *inode, block_t bidx, folio_unlock(folio); folio_end_dropbehind(folio); folio_put(folio); +out_iput: + if (atomic_inode) + iput(atomic_inode); return err; } diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 1694726122e6..939d75663a40 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -863,10 +863,15 @@ 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);