From: Chao Yu chao@kernel.org

[ Upstream commit d7409b05a64f212735f0d33f5f1602051a886eab ]

syzbot reports a f2fs bug as below:

BUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46 Read of size 4 at addr ffff8880739ab220 by task syz-executor200/5097

CPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46 do_read_inode fs/f2fs/inode.c:509 [inline] f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560 f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237 generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413 exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444 exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584 do_handle_to_path fs/fhandle.c:155 [inline] handle_to_path fs/fhandle.c:210 [inline] do_handle_open+0x495/0x650 fs/fhandle.c:226 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

We missed to cover sanity_check_extent_cache() w/ extent cache lock, so, below race case may happen, result in use after free issue.

- f2fs_iget - do_read_inode - f2fs_init_read_extent_tree : add largest extent entry in to cache - shrink - f2fs_shrink_read_extent_tree - __shrink_extent_tree - __detach_extent_node : drop largest extent entry - sanity_check_extent_cache : access et->largest w/o lock

let's refactor sanity_check_extent_cache() to avoid extent cache access and call it before f2fs_init_read_extent_tree() to fix this issue.

Reported-by: syzbot+74ebe2104433e9dc610d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/00000000000009beea061740a531@google... Signed-off-by: Chao Yu chao@kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/extent_cache.c | 48 +++++++++++++++++------------------------- fs/f2fs/f2fs.h | 2 +- fs/f2fs/inode.c | 10 ++++----- 3 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index ad8dfac73bd44..6a9a470345bfc 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -19,34 +19,24 @@ #include "node.h" #include <trace/events/f2fs.h>

-bool sanity_check_extent_cache(struct inode *inode) +bool sanity_check_extent_cache(struct inode *inode, struct page *ipage) { struct f2fs_sb_info *sbi = F2FS_I_SB(inode); - struct f2fs_inode_info *fi = F2FS_I(inode); - struct extent_tree *et = fi->extent_tree[EX_READ]; - struct extent_info *ei; - - if (!et) - return true; + struct f2fs_extent *i_ext = &F2FS_INODE(ipage)->i_ext; + struct extent_info ei;

- ei = &et->largest; - if (!ei->len) - return true; + get_read_extent_info(&ei, i_ext);

- /* Let's drop, if checkpoint got corrupted. */ - if (is_set_ckpt_flags(sbi, CP_ERROR_FLAG)) { - ei->len = 0; - et->largest_updated = true; + if (!ei.len) return true; - }

- if (!f2fs_is_valid_blkaddr(sbi, ei->blk, DATA_GENERIC_ENHANCE) || - !f2fs_is_valid_blkaddr(sbi, ei->blk + ei->len - 1, + if (!f2fs_is_valid_blkaddr(sbi, ei.blk, DATA_GENERIC_ENHANCE) || + !f2fs_is_valid_blkaddr(sbi, ei.blk + ei.len - 1, DATA_GENERIC_ENHANCE)) { set_sbi_flag(sbi, SBI_NEED_FSCK); f2fs_warn(sbi, "%s: inode (ino=%lx) extent info [%u, %u, %u] is incorrect, run fsck to fix", __func__, inode->i_ino, - ei->blk, ei->fofs, ei->len); + ei.blk, ei.fofs, ei.len); return false; } return true; @@ -395,24 +385,22 @@ void f2fs_init_read_extent_tree(struct inode *inode, struct page *ipage)

if (!__may_extent_tree(inode, EX_READ)) { /* drop largest read extent */ - if (i_ext && i_ext->len) { + if (i_ext->len) { f2fs_wait_on_page_writeback(ipage, NODE, true, true); i_ext->len = 0; set_page_dirty(ipage); } - goto out; + set_inode_flag(inode, FI_NO_EXTENT); + return; }

et = __grab_extent_tree(inode, EX_READ);

- if (!i_ext || !i_ext->len) - goto out; - get_read_extent_info(&ei, i_ext);

write_lock(&et->lock); - if (atomic_read(&et->node_cnt)) - goto unlock_out; + if (atomic_read(&et->node_cnt) || !ei.len) + goto skip;

en = __attach_extent_node(sbi, et, &ei, NULL, &et->root.rb_root.rb_node, true); @@ -424,11 +412,13 @@ void f2fs_init_read_extent_tree(struct inode *inode, struct page *ipage) list_add_tail(&en->list, &eti->extent_list); spin_unlock(&eti->extent_lock); } -unlock_out: +skip: + /* Let's drop, if checkpoint got corrupted. */ + if (f2fs_cp_error(sbi)) { + et->largest.len = 0; + et->largest_updated = true; + } write_unlock(&et->lock); -out: - if (!F2FS_I(inode)->extent_tree[EX_READ]) - set_inode_flag(inode, FI_NO_EXTENT); }

void f2fs_init_age_extent_tree(struct inode *inode) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 1252d57228dc6..c70f1314155f5 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -4184,7 +4184,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *sbi); /* * extent_cache.c */ -bool sanity_check_extent_cache(struct inode *inode); +bool sanity_check_extent_cache(struct inode *inode, struct page *ipage); void f2fs_init_extent_tree(struct inode *inode); void f2fs_drop_extent_tree(struct inode *inode); void f2fs_destroy_extent_node(struct inode *inode); diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index abe2f5f043b0d..dd7c0b4749e41 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -508,16 +508,16 @@ static int do_read_inode(struct inode *inode)

init_idisk_time(inode);

- /* Need all the flag bits */ - f2fs_init_read_extent_tree(inode, node_page); - f2fs_init_age_extent_tree(inode); - - if (!sanity_check_extent_cache(inode)) { + if (!sanity_check_extent_cache(inode, node_page)) { f2fs_put_page(node_page, 1); f2fs_handle_error(sbi, ERROR_CORRUPTED_INODE); return -EFSCORRUPTED; }

+ /* Need all the flag bits */ + f2fs_init_read_extent_tree(inode, node_page); + f2fs_init_age_extent_tree(inode); + f2fs_put_page(node_page, 1);

stat_inc_inline_xattr(inode);

From: Edward Adam Davis eadavis@qq.com

[ Upstream commit ce6dede912f064a855acf6f04a04cbb2c25b8c8c ]

[syzbot reported] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 5061 Comm: syz-executor404 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:dtInsertEntry+0xd0c/0x1780 fs/jfs/jfs_dtree.c:3713 ... [Analyze] In dtInsertEntry(), when the pointer h has the same value as p, after writing name in UniStrncpy_to_le(), p->header.flag will be cleared. This will cause the previously true judgment "p->header.flag & BT-LEAF" to change to no after writing the name operation, this leads to entering an incorrect branch and accessing the uninitialized object ih when judging this condition for the second time.

[Fix] After got the page, check freelist first, if freelist == 0 then exit dtInsert() and return -EINVAL.

Reported-by: syzbot+bba84aef3a26fb93deb9@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis eadavis@qq.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_dtree.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c index 031d8f570f581..5d3127ca68a42 100644 --- a/fs/jfs/jfs_dtree.c +++ b/fs/jfs/jfs_dtree.c @@ -834,6 +834,8 @@ int dtInsert(tid_t tid, struct inode *ip, * the full page. */ DT_GETSEARCH(ip, btstack->top, bn, mp, p, index); + if (p->header.freelist == 0) + return -EINVAL;

/* * insert entry for new key

From: David Howells dhowells@redhat.com

[ Upstream commit c3a5e3e872f3688ae0dc57bb78ca633921d96a91 ]

When using cachefiles, lockdep may emit something similar to the circular locking dependency notice below. The problem appears to stem from the following:

(1) Cachefiles manipulates xattrs on the files in its cache when called from ->writepages().

(2) The setxattr() and removexattr() system call handlers get the name (and value) from userspace after taking the sb_writers lock, putting accesses of the vma->vm_lock and mm->mmap_lock inside of that.

(3) The afs filesystem uses a per-inode lock to prevent multiple revalidation RPCs and in writeback vs truncate to prevent parallel operations from deadlocking against the server on one side and local page locks on the other.

Fix this by moving the getting of the name and value in {get,remove}xattr() outside of the sb_writers lock. This also has the minor benefits that we don't need to reget these in the event of a retry and we never try to take the sb_writers lock in the event we can't pull the name and value into the kernel.

Alternative approaches that might fix this include moving the dispatch of a write to the cache off to a workqueue or trying to do without the validation lock in afs. Note that this might also affect other filesystems that use netfslib and/or cachefiles.

====================================================== WARNING: possible circular locking dependency detected 6.10.0-build2+ #956 Not tainted ------------------------------------------------------ fsstress/6050 is trying to acquire lock: ffff888138fd82f0 (mapping.invalidate_lock#3){++++}-{3:3}, at: filemap_fault+0x26e/0x8b0

but task is already holding lock: ffff888113f26d18 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x165/0x250

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (&vma->vm_lock->lock){++++}-{3:3}: __lock_acquire+0xaf0/0xd80 lock_acquire.part.0+0x103/0x280 down_write+0x3b/0x50 vma_start_write+0x6b/0xa0 vma_link+0xcc/0x140 insert_vm_struct+0xb7/0xf0 alloc_bprm+0x2c1/0x390 kernel_execve+0x65/0x1a0 call_usermodehelper_exec_async+0x14d/0x190 ret_from_fork+0x24/0x40 ret_from_fork_asm+0x1a/0x30

-> #3 (&mm->mmap_lock){++++}-{3:3}: __lock_acquire+0xaf0/0xd80 lock_acquire.part.0+0x103/0x280 __might_fault+0x7c/0xb0 strncpy_from_user+0x25/0x160 removexattr+0x7f/0x100 __do_sys_fremovexattr+0x7e/0xb0 do_syscall_64+0x9f/0x100 entry_SYSCALL_64_after_hwframe+0x76/0x7e

-> #2 (sb_writers#14){.+.+}-{0:0}: __lock_acquire+0xaf0/0xd80 lock_acquire.part.0+0x103/0x280 percpu_down_read+0x3c/0x90 vfs_iocb_iter_write+0xe9/0x1d0 __cachefiles_write+0x367/0x430 cachefiles_issue_write+0x299/0x2f0 netfs_advance_write+0x117/0x140 netfs_write_folio.isra.0+0x5ca/0x6e0 netfs_writepages+0x230/0x2f0 afs_writepages+0x4d/0x70 do_writepages+0x1e8/0x3e0 filemap_fdatawrite_wbc+0x84/0xa0 __filemap_fdatawrite_range+0xa8/0xf0 file_write_and_wait_range+0x59/0x90 afs_release+0x10f/0x270 __fput+0x25f/0x3d0 __do_sys_close+0x43/0x70 do_syscall_64+0x9f/0x100 entry_SYSCALL_64_after_hwframe+0x76/0x7e

-> #1 (&vnode->validate_lock){++++}-{3:3}: __lock_acquire+0xaf0/0xd80 lock_acquire.part.0+0x103/0x280 down_read+0x95/0x200 afs_writepages+0x37/0x70 do_writepages+0x1e8/0x3e0 filemap_fdatawrite_wbc+0x84/0xa0 filemap_invalidate_inode+0x167/0x1e0 netfs_unbuffered_write_iter+0x1bd/0x2d0 vfs_write+0x22e/0x320 ksys_write+0xbc/0x130 do_syscall_64+0x9f/0x100 entry_SYSCALL_64_after_hwframe+0x76/0x7e

-> #0 (mapping.invalidate_lock#3){++++}-{3:3}: check_noncircular+0x119/0x160 check_prev_add+0x195/0x430 __lock_acquire+0xaf0/0xd80 lock_acquire.part.0+0x103/0x280 down_read+0x95/0x200 filemap_fault+0x26e/0x8b0 __do_fault+0x57/0xd0 do_pte_missing+0x23b/0x320 __handle_mm_fault+0x2d4/0x320 handle_mm_fault+0x14f/0x260 do_user_addr_fault+0x2a2/0x500 exc_page_fault+0x71/0x90 asm_exc_page_fault+0x22/0x30

other info that might help us debug this:

Chain exists of: mapping.invalidate_lock#3 --> &mm->mmap_lock --> &vma->vm_lock->lock

Possible unsafe locking scenario:

CPU0 CPU1 ---- ---- rlock(&vma->vm_lock->lock); lock(&mm->mmap_lock); lock(&vma->vm_lock->lock); rlock(mapping.invalidate_lock#3);

*** DEADLOCK ***

1 lock held by fsstress/6050: #0: ffff888113f26d18 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x165/0x250

stack backtrace: CPU: 0 PID: 6050 Comm: fsstress Not tainted 6.10.0-build2+ #956 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 Call Trace: <TASK> dump_stack_lvl+0x57/0x80 check_noncircular+0x119/0x160 ? queued_spin_lock_slowpath+0x4be/0x510 ? __pfx_check_noncircular+0x10/0x10 ? __pfx_queued_spin_lock_slowpath+0x10/0x10 ? mark_lock+0x47/0x160 ? init_chain_block+0x9c/0xc0 ? add_chain_block+0x84/0xf0 check_prev_add+0x195/0x430 __lock_acquire+0xaf0/0xd80 ? __pfx___lock_acquire+0x10/0x10 ? __lock_release.isra.0+0x13b/0x230 lock_acquire.part.0+0x103/0x280 ? filemap_fault+0x26e/0x8b0 ? __pfx_lock_acquire.part.0+0x10/0x10 ? rcu_is_watching+0x34/0x60 ? lock_acquire+0xd7/0x120 down_read+0x95/0x200 ? filemap_fault+0x26e/0x8b0 ? __pfx_down_read+0x10/0x10 ? __filemap_get_folio+0x25/0x1a0 filemap_fault+0x26e/0x8b0 ? __pfx_filemap_fault+0x10/0x10 ? find_held_lock+0x7c/0x90 ? __pfx___lock_release.isra.0+0x10/0x10 ? __pte_offset_map+0x99/0x110 __do_fault+0x57/0xd0 do_pte_missing+0x23b/0x320 __handle_mm_fault+0x2d4/0x320 ? __pfx___handle_mm_fault+0x10/0x10 handle_mm_fault+0x14f/0x260 do_user_addr_fault+0x2a2/0x500 exc_page_fault+0x71/0x90 asm_exc_page_fault+0x22/0x30

Signed-off-by: David Howells dhowells@redhat.com Link: https://lore.kernel.org/r/2136178.1721725194@warthog.procyon.org.uk cc: Alexander Viro viro@zeniv.linux.org.uk cc: Christian Brauner brauner@kernel.org cc: Jan Kara jack@suse.cz cc: Jeff Layton jlayton@kernel.org cc: Gao Xiang xiang@kernel.org cc: Matthew Wilcox willy@infradead.org cc: netfs@lists.linux.dev cc: linux-erofs@lists.ozlabs.org cc: linux-fsdevel@vger.kernel.org [brauner: fix minor issues] Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/xattr.c | 91 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 48 insertions(+), 43 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c index efd4736bc94b0..c20046548f218 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -631,10 +631,9 @@ int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, ctx->kvalue, ctx->size, ctx->flags); }

-static long -setxattr(struct mnt_idmap *idmap, struct dentry *d, - const char __user *name, const void __user *value, size_t size, - int flags) +static int path_setxattr(const char __user *pathname, + const char __user *name, const void __user *value, + size_t size, int flags, unsigned int lookup_flags) { struct xattr_name kname; struct xattr_ctx ctx = { @@ -644,33 +643,20 @@ setxattr(struct mnt_idmap *idmap, struct dentry *d, .kname = &kname, .flags = flags, }; + struct path path; int error;

error = setxattr_copy(name, &ctx); if (error) return error;

- error = do_setxattr(idmap, d, &ctx); - - kvfree(ctx.kvalue); - return error; -} - -static int path_setxattr(const char __user *pathname, - const char __user *name, const void __user *value, - size_t size, int flags, unsigned int lookup_flags) -{ - struct path path; - int error; - retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) - return error; + goto out; error = mnt_want_write(path.mnt); if (!error) { - error = setxattr(mnt_idmap(path.mnt), path.dentry, name, - value, size, flags); + error = do_setxattr(mnt_idmap(path.mnt), path.dentry, &ctx); mnt_drop_write(path.mnt); } path_put(&path); @@ -678,6 +664,9 @@ static int path_setxattr(const char __user *pathname, lookup_flags |= LOOKUP_REVAL; goto retry; } + +out: + kvfree(ctx.kvalue); return error; }

@@ -698,20 +687,32 @@ SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, const void __user *,value, size_t, size, int, flags) { - struct fd f = fdget(fd); - int error = -EBADF; + struct xattr_name kname; + struct xattr_ctx ctx = { + .cvalue = value, + .kvalue = NULL, + .size = size, + .kname = &kname, + .flags = flags, + }; + int error;

+ CLASS(fd, f)(fd); if (!f.file) - return error; + return -EBADF; + audit_file(f.file); + error = setxattr_copy(name, &ctx); + if (error) + return error; + error = mnt_want_write_file(f.file); if (!error) { - error = setxattr(file_mnt_idmap(f.file), - f.file->f_path.dentry, name, - value, size, flags); + error = do_setxattr(file_mnt_idmap(f.file), + f.file->f_path.dentry, &ctx); mnt_drop_write_file(f.file); } - fdput(f); + kvfree(ctx.kvalue); return error; }

@@ -900,9 +901,17 @@ SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) * Extended attribute REMOVE operations */ static long -removexattr(struct mnt_idmap *idmap, struct dentry *d, - const char __user *name) +removexattr(struct mnt_idmap *idmap, struct dentry *d, const char *name) { + if (is_posix_acl_xattr(name)) + return vfs_remove_acl(idmap, d, name); + return vfs_removexattr(idmap, d, name); +} + +static int path_removexattr(const char __user *pathname, + const char __user *name, unsigned int lookup_flags) +{ + struct path path; int error; char kname[XATTR_NAME_MAX + 1];

@@ -911,25 +920,13 @@ removexattr(struct mnt_idmap *idmap, struct dentry *d, error = -ERANGE; if (error < 0) return error; - - if (is_posix_acl_xattr(kname)) - return vfs_remove_acl(idmap, d, kname); - - return vfs_removexattr(idmap, d, kname); -} - -static int path_removexattr(const char __user *pathname, - const char __user *name, unsigned int lookup_flags) -{ - struct path path; - int error; retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); if (error) return error; error = mnt_want_write(path.mnt); if (!error) { - error = removexattr(mnt_idmap(path.mnt), path.dentry, name); + error = removexattr(mnt_idmap(path.mnt), path.dentry, kname); mnt_drop_write(path.mnt); } path_put(&path); @@ -955,15 +952,23 @@ SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) { struct fd f = fdget(fd); + char kname[XATTR_NAME_MAX + 1]; int error = -EBADF;

if (!f.file) return error; audit_file(f.file); + + error = strncpy_from_user(kname, name, sizeof(kname)); + if (error == 0 || error == sizeof(kname)) + error = -ERANGE; + if (error < 0) + return error; + error = mnt_want_write_file(f.file); if (!error) { error = removexattr(file_mnt_idmap(f.file), - f.file->f_path.dentry, name); + f.file->f_path.dentry, kname); mnt_drop_write_file(f.file); } fdput(f);