From e79a33270d05f711e985b9524a392fd45ad3e93f Mon Sep 17 00:00:00 2001 From: Su Yue Date: Tue, 6 Jun 2017 17:57:01 +0800 Subject: btrfs: Check name_len with boundary in verify dir_item Originally, verify_dir_item verifies name_len of dir_item with fixed values but not item boundary. If corrupted name_len was not bigger than the fixed value, for example 255, the function will think the dir_item is fine. And then reading beyond boundary will cause crash. Example: 1. Corrupt one dir_item name_len to be 255. 2. Run 'ls -lar /mnt/test/ > /dev/null' dmesg: [ 48.451449] BTRFS info (device vdb1): disk space caching is enabled [ 48.451453] BTRFS info (device vdb1): has skinny extents [ 48.489420] general protection fault: 0000 [#1] SMP [ 48.489571] Modules linked in: ext4 jbd2 mbcache btrfs xor raid6_pq [ 48.489716] CPU: 1 PID: 2710 Comm: ls Not tainted 4.10.0-rc1 #5 [ 48.489853] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 [ 48.490008] task: ffff880035df1bc0 task.stack: ffffc90004800000 [ 48.490008] RIP: 0010:read_extent_buffer+0xd2/0x190 [btrfs] [ 48.490008] RSP: 0018:ffffc90004803d98 EFLAGS: 00010202 [ 48.490008] RAX: 000000000000001b RBX: 000000000000001b RCX: 0000000000000000 [ 48.490008] RDX: ffff880079dbf36c RSI: 0005080000000000 RDI: ffff880079dbf368 [ 48.490008] RBP: ffffc90004803dc8 R08: ffff880078e8cc48 R09: ffff880000000000 [ 48.490008] R10: 0000160000000000 R11: 0000000000001000 R12: ffff880079dbf288 [ 48.490008] R13: ffff880078e8ca88 R14: 0000000000000003 R15: ffffc90004803e20 [ 48.490008] FS: 00007fef50c60800(0000) GS:ffff88007d400000(0000) knlGS:0000000000000000 [ 48.490008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 48.490008] CR2: 000055f335ac2ff8 CR3: 000000007356d000 CR4: 00000000001406e0 [ 48.490008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 48.490008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 48.490008] Call Trace: [ 48.490008] btrfs_real_readdir+0x3b7/0x4a0 [btrfs] [ 48.490008] iterate_dir+0x181/0x1b0 [ 48.490008] SyS_getdents+0xa7/0x150 [ 48.490008] ? fillonedir+0x150/0x150 [ 48.490008] entry_SYSCALL_64_fastpath+0x18/0xad [ 48.490008] RIP: 0033:0x7fef5032546b [ 48.490008] RSP: 002b:00007ffeafcdb830 EFLAGS: 00000206 ORIG_RAX: 000000000000004e [ 48.490008] RAX: ffffffffffffffda RBX: 00007fef5061db38 RCX: 00007fef5032546b [ 48.490008] RDX: 0000000000008000 RSI: 000055f335abaff0 RDI: 0000000000000003 [ 48.490008] RBP: 00007fef5061dae0 R08: 00007fef5061db48 R09: 0000000000000000 [ 48.490008] R10: 000055f335abafc0 R11: 0000000000000206 R12: 00007fef5061db38 [ 48.490008] R13: 0000000000008040 R14: 00007fef5061db38 R15: 000000000000270e [ 48.490008] RIP: read_extent_buffer+0xd2/0x190 [btrfs] RSP: ffffc90004803d98 [ 48.499455] ---[ end trace 321920d8e8339505 ]--- Fix it by adding a parameter @slot and check name_len with item boundary by calling btrfs_is_name_len_valid. Signed-off-by: Su Yue rev Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index ccfe9fe7754a..1930f28edcdd 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -1841,7 +1841,7 @@ static noinline int replay_one_dir_item(struct btrfs_trans_handle *trans, ptr_end = ptr + item_size; while (ptr < ptr_end) { di = (struct btrfs_dir_item *)ptr; - if (verify_dir_item(fs_info, eb, di)) + if (verify_dir_item(fs_info, eb, slot, di)) return -EIO; name_len = btrfs_dir_name_len(eb, di); ret = replay_one_name(trans, root, path, eb, di, key); @@ -2017,7 +2017,7 @@ again: ptr_end = ptr + item_size; while (ptr < ptr_end) { di = (struct btrfs_dir_item *)ptr; - if (verify_dir_item(fs_info, eb, di)) { + if (verify_dir_item(fs_info, eb, slot, di)) { ret = -EIO; goto out; } -- cgit v1.2.1 From 26a836cec2ea38329ddf3f049c78e9b94e500670 Mon Sep 17 00:00:00 2001 From: Su Yue Date: Tue, 6 Jun 2017 17:57:02 +0800 Subject: btrfs: Check name_len on add_inode_ref call path replay_one_buffer first reads buffers and dispatches items accroding to the item type. In this patch, add_inode_ref handles inode_ref and inode_extref. Then add_inode_ref calls ref_get_fields and extref_get_fields to read ref/extref name for the first time. So checking name_len before reading those two is fine. add_inode_ref also calls inode_in_dir to match ref/extref in parent_dir. The call graph includes btrfs_match_dir_item_name to read dir_item name in the parent dir. Checking first dir_item is not enough. Change it to verify every dir_item while doing matches. Signed-off-by: Su Yue Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 1930f28edcdd..11cf38fb3a49 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -1175,15 +1175,19 @@ next: return 0; } -static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr, - u32 *namelen, char **name, u64 *index, - u64 *parent_objectid) +static int extref_get_fields(struct extent_buffer *eb, int slot, + unsigned long ref_ptr, u32 *namelen, char **name, + u64 *index, u64 *parent_objectid) { struct btrfs_inode_extref *extref; extref = (struct btrfs_inode_extref *)ref_ptr; *namelen = btrfs_inode_extref_name_len(eb, extref); + if (!btrfs_is_name_len_valid(eb, slot, (unsigned long)&extref->name, + *namelen)) + return -EIO; + *name = kmalloc(*namelen, GFP_NOFS); if (*name == NULL) return -ENOMEM; @@ -1198,14 +1202,19 @@ static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr, return 0; } -static int ref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr, - u32 *namelen, char **name, u64 *index) +static int ref_get_fields(struct extent_buffer *eb, int slot, + unsigned long ref_ptr, u32 *namelen, char **name, + u64 *index) { struct btrfs_inode_ref *ref; ref = (struct btrfs_inode_ref *)ref_ptr; *namelen = btrfs_inode_ref_name_len(eb, ref); + if (!btrfs_is_name_len_valid(eb, slot, (unsigned long)(ref + 1), + *namelen)) + return -EIO; + *name = kmalloc(*namelen, GFP_NOFS); if (*name == NULL) return -ENOMEM; @@ -1280,8 +1289,8 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, while (ref_ptr < ref_end) { if (log_ref_ver) { - ret = extref_get_fields(eb, ref_ptr, &namelen, &name, - &ref_index, &parent_objectid); + ret = extref_get_fields(eb, slot, ref_ptr, &namelen, + &name, &ref_index, &parent_objectid); /* * parent object can change from one array * item to another. @@ -1293,8 +1302,8 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, goto out; } } else { - ret = ref_get_fields(eb, ref_ptr, &namelen, &name, - &ref_index); + ret = ref_get_fields(eb, slot, ref_ptr, &namelen, + &name, &ref_index); } if (ret) goto out; -- cgit v1.2.1 From 8ee8c2d62d5f9e7d1e592426d3d0b941df29f688 Mon Sep 17 00:00:00 2001 From: Su Yue Date: Tue, 6 Jun 2017 17:57:03 +0800 Subject: btrfs: Verify dir_item in replay_xattr_deletes replay_xattr_deletes calls btrfs_search_slot to get buffer and reads name. Call verify_dir_item to check name_len in replay_xattr_deletes to avoid reading out of boundary. Signed-off-by: Su Yue Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 11cf38fb3a49..06c7ceb07282 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -2111,6 +2111,7 @@ static int replay_xattr_deletes(struct btrfs_trans_handle *trans, struct btrfs_path *path, const u64 ino) { + struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_key search_key; struct btrfs_path *log_path; int i; @@ -2152,6 +2153,12 @@ process_leaf: u32 this_len = sizeof(*di) + name_len + data_len; char *name; + ret = verify_dir_item(fs_info, path->nodes[0], + path->slots[0], di); + if (ret) { + ret = -EIO; + goto out; + } name = kmalloc(name_len, GFP_NOFS); if (!name) { ret = -ENOMEM; -- cgit v1.2.1 From 3c1d41844896f59ac771daf146a5329525dc87c5 Mon Sep 17 00:00:00 2001 From: Su Yue Date: Tue, 6 Jun 2017 17:57:04 +0800 Subject: btrfs: Check name_len in btrfs_check_ref_name_override In btrfs_log_inode, btrfs_search_forward gets the buffer and then btrfs_check_ref_name_override will read name from ref/extref for the first time. Call btrfs_is_name_len_valid before reading name. Signed-off-by: Su Yue Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/tree-log.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 06c7ceb07282..f20ef211a73d 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4562,6 +4562,12 @@ static int btrfs_check_ref_name_override(struct extent_buffer *eb, this_len = sizeof(*extref) + this_name_len; } + ret = btrfs_is_name_len_valid(eb, slot, name_ptr, + this_name_len); + if (!ret) { + ret = -EIO; + goto out; + } if (this_name_len > name_len) { char *new_name; -- cgit v1.2.1