The patch below does not apply to the 4.4-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 <stable@xxxxxxxxxxxxxxx>. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From c6ad7fd16657ebd34a87a97d9588195aae87597d Mon Sep 17 00:00:00 2001 From: Chao Yu <chao@xxxxxxxxxx> Date: Wed, 14 Sep 2022 19:51:51 +0800 Subject: [PATCH] f2fs: fix to do sanity check on summary info As Wenqing Liu reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216456 BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs] Read of size 4 at addr ffff8881464dcd80 by task mount/1013 CPU: 3 PID: 1013 Comm: mount Tainted: G W 6.0.0-rc4 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 Call Trace: dump_stack_lvl+0x45/0x5e print_report.cold+0xf3/0x68d kasan_report+0xa8/0x130 recover_data+0x63ae/0x6ae0 [f2fs] f2fs_recover_fsync_data+0x120d/0x1fc0 [f2fs] f2fs_fill_super+0x4665/0x61e0 [f2fs] mount_bdev+0x2cf/0x3b0 legacy_get_tree+0xed/0x1d0 vfs_get_tree+0x81/0x2b0 path_mount+0x47e/0x19d0 do_mount+0xce/0xf0 __x64_sys_mount+0x12c/0x1a0 do_syscall_64+0x38/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd The root cause is: in fuzzed image, SSA table is corrupted: ofs_in_node is larger than ADDRS_PER_PAGE(), result in out-of-range access on 4k-size page. - recover_data - do_recover_data - check_index_in_prev_nodes - f2fs_data_blkaddr This patch adds sanity check on summary info in recovery and GC flow in where the flows rely on them. After patch: [ 29.310883] F2FS-fs (loop0): Inconsistent ofs_in_node:65286 in summary, ino:0, nid:6, max:1018 Cc: stable@xxxxxxxxxxxxxxx Reported-by: Wenqing Liu <wenqingliu0120@xxxxxxxxx> Signed-off-by: Chao Yu <chao@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index fd400d148afb..3a820e5cdaee 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1078,7 +1078,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, { struct page *node_page; nid_t nid; - unsigned int ofs_in_node; + unsigned int ofs_in_node, max_addrs; block_t source_blkaddr; nid = le32_to_cpu(sum->nid); @@ -1104,6 +1104,14 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, return false; } + max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE : + DEF_ADDRS_PER_BLOCK; + if (ofs_in_node >= max_addrs) { + f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u", + ofs_in_node, dni->ino, dni->nid, max_addrs); + return false; + } + *nofs = ofs_of_node(node_page); source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node); f2fs_put_page(node_page, 1); diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c index 8326003e6918..5c9facec98f6 100644 --- a/fs/f2fs/recovery.c +++ b/fs/f2fs/recovery.c @@ -474,7 +474,7 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi, struct dnode_of_data tdn = *dn; nid_t ino, nid; struct inode *inode; - unsigned int offset; + unsigned int offset, ofs_in_node, max_addrs; block_t bidx; int i; @@ -501,15 +501,24 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi, got_it: /* Use the locked dnode page and inode */ nid = le32_to_cpu(sum.nid); + ofs_in_node = le16_to_cpu(sum.ofs_in_node); + + max_addrs = ADDRS_PER_PAGE(dn->node_page, dn->inode); + if (ofs_in_node >= max_addrs) { + f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%lu, nid:%u, max:%u", + ofs_in_node, dn->inode->i_ino, nid, max_addrs); + return -EFSCORRUPTED; + } + if (dn->inode->i_ino == nid) { tdn.nid = nid; if (!dn->inode_page_locked) lock_page(dn->inode_page); tdn.node_page = dn->inode_page; - tdn.ofs_in_node = le16_to_cpu(sum.ofs_in_node); + tdn.ofs_in_node = ofs_in_node; goto truncate_out; } else if (dn->nid == nid) { - tdn.ofs_in_node = le16_to_cpu(sum.ofs_in_node); + tdn.ofs_in_node = ofs_in_node; goto truncate_out; }
