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 C920E3D34AB for ; Fri, 3 Jul 2026 13:23:45 +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=1783085027; cv=none; b=l5ZPxDGfkDciXt9TKrvYV2/b7n47rucWqTBn0YzXlg3VfJcyjkhdpmRd4sg+WloudKvK2NL8PFK0PFX0QP5HTyjy7rghA332MEZzQK8mjB1YbFX7pdgsgnm0Rdno27StiapxJb5C0BjkjuQx6akTF6ChC1tNW+M4vrEsZ7YGEPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783085027; c=relaxed/simple; bh=Lb5sSBOZ0OKXDu2ZauWRBrg8zRXO2hbRHe94LdNgsJc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tviIO+QbjwFCrqcD+J4B/39NbvutOG0QDYkebx7Ys4WqLV8+BPpuW6JH0DcoZZ4kCAEQbE3WY2lSrH37t2vqXOkFyAJdp24ufBX7wfiOeqpSRQNNYSSFyVBt0KklKF/41jVMzXqYatZLQSQUJvta9wQJx9EX0w9nfr+lHVWqPd4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Nq8g2wKp; 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="Nq8g2wKp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A175C1F000E9; Fri, 3 Jul 2026 13:23:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783085025; bh=mUuKXjYPypSHdEoskt18s4yOKAj9aZtDFZeDC3GevYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Nq8g2wKpcnvVVvCCGlmVzgN6H/j++YHVEbY6zbqXyXuenE4onm0Cm2UvTNcyjQcs/ MPrcWwQ7oCAd4goXV1CaLIbjRys9jXkVdtOHgtp4H9xbKWTiCU2mTaQzaqzHWa/IV+ /rwygnn7kvYkIPNQtxMf2o+ecZmA7jprwhBTzp51jmLP3cF/GM28uE41g9JBBooz2c 0xvQDbrQa8mc7Ez9k//yIasg1sBgUP0bFdYYaU/RxGBt4lQPXx2T2sq/Crvsh3agB+ QnVn1kktdDT+IdELWs/SAv5y7sG49OM6LyfSZvNFSnhObqhkYDQ09iC0/xmUWbz3Hs aJKW1h/eMZEpw== From: Sasha Levin To: stable@vger.kernel.org Cc: Chao Yu , stable@kernel.org, Daeho Jeong , Sunmin Jeong , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12.y] f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode Date: Fri, 3 Jul 2026 09:23:42 -0400 Message-ID: <20260703132342.4101156-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026070242-sardine-wiring-9d91@gregkh> References: <2026070242-sardine-wiring-9d91@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 6e09b80c0c3779..b8a9412ca1dc83 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1213,8 +1213,8 @@ 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 = { @@ -1229,9 +1229,22 @@ 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)) { @@ -1288,11 +1301,16 @@ 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; } @@ -1303,8 +1321,8 @@ 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, @@ -1326,10 +1344,23 @@ 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; @@ -1456,6 +1487,9 @@ 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 9180693b933f83..4aac423f2eae01 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -834,10 +834,15 @@ 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