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authorJohn Johansen <john.johansen@canonical.com>2017-11-20 23:24:09 -0800
committerJohn Johansen <john.johansen@canonical.com>2017-11-21 02:17:16 -0800
commitfeb3c766a3ab32d233aaff7db13afd9ba5bc142d (patch)
tree59b48447feb2bf23a53df1b2ead7d02fd440c957 /security/apparmor/apparmorfs.c
parent5d7c44ef5e4f0149c9fb99faeae41e930485a1ec (diff)
downloadlinux-feb3c766a3ab32d233aaff7db13afd9ba5bc142d.tar.gz
apparmor: fix possible recursive lock warning in __aa_create_ns
Use mutex_lock_nested to provide lockdep the parent child lock ordering of the tree. This fixes the lockdep Warning [ 305.275177] ============================================ [ 305.275178] WARNING: possible recursive locking detected [ 305.275179] 4.14.0-rc7+ #320 Not tainted [ 305.275180] -------------------------------------------- [ 305.275181] apparmor_parser/1339 is trying to acquire lock: [ 305.275182] (&ns->lock){+.+.}, at: [<ffffffff970544dd>] __aa_create_ns+0x6d/0x1e0 [ 305.275187] but task is already holding lock: [ 305.275187] (&ns->lock){+.+.}, at: [<ffffffff97054b5d>] aa_prepare_ns+0x3d/0xd0 [ 305.275190] other info that might help us debug this: [ 305.275191] Possible unsafe locking scenario: [ 305.275192] CPU0 [ 305.275193] ---- [ 305.275193] lock(&ns->lock); [ 305.275194] lock(&ns->lock); [ 305.275195] *** DEADLOCK *** [ 305.275196] May be due to missing lock nesting notation [ 305.275198] 2 locks held by apparmor_parser/1339: [ 305.275198] #0: (sb_writers#10){.+.+}, at: [<ffffffff96e9c6b7>] vfs_write+0x1a7/0x1d0 [ 305.275202] #1: (&ns->lock){+.+.}, at: [<ffffffff97054b5d>] aa_prepare_ns+0x3d/0xd0 [ 305.275205] stack backtrace: [ 305.275207] CPU: 1 PID: 1339 Comm: apparmor_parser Not tainted 4.14.0-rc7+ #320 [ 305.275208] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1ubuntu1 04/01/2014 [ 305.275209] Call Trace: [ 305.275212] dump_stack+0x85/0xcb [ 305.275214] __lock_acquire+0x141c/0x1460 [ 305.275216] ? __aa_create_ns+0x6d/0x1e0 [ 305.275218] ? ___slab_alloc+0x183/0x540 [ 305.275219] ? ___slab_alloc+0x183/0x540 [ 305.275221] lock_acquire+0xed/0x1e0 [ 305.275223] ? lock_acquire+0xed/0x1e0 [ 305.275224] ? __aa_create_ns+0x6d/0x1e0 [ 305.275227] __mutex_lock+0x89/0x920 [ 305.275228] ? __aa_create_ns+0x6d/0x1e0 [ 305.275230] ? trace_hardirqs_on_caller+0x11f/0x190 [ 305.275231] ? __aa_create_ns+0x6d/0x1e0 [ 305.275233] ? __lockdep_init_map+0x57/0x1d0 [ 305.275234] ? lockdep_init_map+0x9/0x10 [ 305.275236] ? __rwlock_init+0x32/0x60 [ 305.275238] mutex_lock_nested+0x1b/0x20 [ 305.275240] ? mutex_lock_nested+0x1b/0x20 [ 305.275241] __aa_create_ns+0x6d/0x1e0 [ 305.275243] aa_prepare_ns+0xc2/0xd0 [ 305.275245] aa_replace_profiles+0x168/0xf30 [ 305.275247] ? __might_fault+0x85/0x90 [ 305.275250] policy_update+0xb9/0x380 [ 305.275252] profile_load+0x7e/0x90 [ 305.275254] __vfs_write+0x28/0x150 [ 305.275256] ? rcu_read_lock_sched_held+0x72/0x80 [ 305.275257] ? rcu_sync_lockdep_assert+0x2f/0x60 [ 305.275259] ? __sb_start_write+0xdc/0x1c0 [ 305.275261] ? vfs_write+0x1a7/0x1d0 [ 305.275262] vfs_write+0xca/0x1d0 [ 305.275264] ? trace_hardirqs_on_caller+0x11f/0x190 [ 305.275266] SyS_write+0x49/0xa0 [ 305.275268] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 305.275271] RIP: 0033:0x7fa6b22e8c74 [ 305.275272] RSP: 002b:00007ffeaaee6288 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 305.275273] RAX: ffffffffffffffda RBX: 00007ffeaaee62a4 RCX: 00007fa6b22e8c74 [ 305.275274] RDX: 0000000000000a51 RSI: 00005566a8198c10 RDI: 0000000000000004 [ 305.275275] RBP: 0000000000000a39 R08: 0000000000000a51 R09: 0000000000000000 [ 305.275276] R10: 0000000000000000 R11: 0000000000000246 R12: 00005566a8198c10 [ 305.275277] R13: 0000000000000004 R14: 00005566a72ecb88 R15: 00005566a72ec3a8 Fixes: 73688d1ed0b8 ("apparmor: refactor prepare_ns() and make usable from different views") Signed-off-by: John Johansen <john.johansen@canonical.com>
Diffstat (limited to 'security/apparmor/apparmorfs.c')
-rw-r--r--security/apparmor/apparmorfs.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index caaf51dda648..8542e9a55e1b 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -533,7 +533,7 @@ static ssize_t ns_revision_read(struct file *file, char __user *buf,
long last_read;
int avail;
- mutex_lock(&rev->ns->lock);
+ mutex_lock_nested(&rev->ns->lock, rev->ns->level);
last_read = rev->last_read;
if (last_read == rev->ns->revision) {
mutex_unlock(&rev->ns->lock);
@@ -543,7 +543,7 @@ static ssize_t ns_revision_read(struct file *file, char __user *buf,
last_read !=
READ_ONCE(rev->ns->revision)))
return -ERESTARTSYS;
- mutex_lock(&rev->ns->lock);
+ mutex_lock_nested(&rev->ns->lock, rev->ns->level);
}
avail = sprintf(buffer, "%ld\n", rev->ns->revision);
@@ -577,7 +577,7 @@ static unsigned int ns_revision_poll(struct file *file, poll_table *pt)
unsigned int mask = 0;
if (rev) {
- mutex_lock(&rev->ns->lock);
+ mutex_lock_nested(&rev->ns->lock, rev->ns->level);
poll_wait(file, &rev->ns->wait, pt);
if (rev->last_read < rev->ns->revision)
mask |= POLLIN | POLLRDNORM;
@@ -1643,7 +1643,7 @@ static int ns_mkdir_op(struct inode *dir, struct dentry *dentry, umode_t mode)
*/
inode_unlock(dir);
error = simple_pin_fs(&aafs_ops, &aafs_mnt, &aafs_count);
- mutex_lock(&parent->lock);
+ mutex_lock_nested(&parent->lock, parent->level);
inode_lock_nested(dir, I_MUTEX_PARENT);
if (error)
goto out;
@@ -1692,7 +1692,7 @@ static int ns_rmdir_op(struct inode *dir, struct dentry *dentry)
inode_unlock(dir);
inode_unlock(dentry->d_inode);
- mutex_lock(&parent->lock);
+ mutex_lock_nested(&parent->lock, parent->level);
ns = aa_get_ns(__aa_findn_ns(&parent->sub_ns, dentry->d_name.name,
dentry->d_name.len));
if (!ns) {
@@ -1747,7 +1747,7 @@ void __aafs_ns_rmdir(struct aa_ns *ns)
__aafs_profile_rmdir(child);
list_for_each_entry(sub, &ns->sub_ns, base.list) {
- mutex_lock(&sub->lock);
+ mutex_lock_nested(&sub->lock, sub->level);
__aafs_ns_rmdir(sub);
mutex_unlock(&sub->lock);
}
@@ -1877,7 +1877,7 @@ int __aafs_ns_mkdir(struct aa_ns *ns, struct dentry *parent, const char *name,
/* subnamespaces */
list_for_each_entry(sub, &ns->sub_ns, base.list) {
- mutex_lock(&sub->lock);
+ mutex_lock_nested(&sub->lock, sub->level);
error = __aafs_ns_mkdir(sub, ns_subns_dir(ns), NULL, NULL);
mutex_unlock(&sub->lock);
if (error)
@@ -1921,7 +1921,7 @@ static struct aa_ns *__next_ns(struct aa_ns *root, struct aa_ns *ns)
/* is next namespace a child */
if (!list_empty(&ns->sub_ns)) {
next = list_first_entry(&ns->sub_ns, typeof(*ns), base.list);
- mutex_lock(&next->lock);
+ mutex_lock_nested(&next->lock, next->level);
return next;
}
@@ -1931,7 +1931,7 @@ static struct aa_ns *__next_ns(struct aa_ns *root, struct aa_ns *ns)
mutex_unlock(&ns->lock);
next = list_next_entry(ns, base.list);
if (!list_entry_is_head(next, &parent->sub_ns, base.list)) {
- mutex_lock(&next->lock);
+ mutex_lock_nested(&next->lock, next->level);
return next;
}
ns = parent;
@@ -2039,7 +2039,7 @@ static void *p_start(struct seq_file *f, loff_t *pos)
f->private = root;
/* find the first profile */
- mutex_lock(&root->lock);
+ mutex_lock_nested(&root->lock, root->level);
profile = __first_profile(root, root);
/* skip to position */
@@ -2491,7 +2491,7 @@ static int __init aa_create_aafs(void)
ns_subrevision(root_ns) = dent;
/* policy tree referenced by magic policy symlink */
- mutex_lock(&root_ns->lock);
+ mutex_lock_nested(&root_ns->lock, root_ns->level);
error = __aafs_ns_mkdir(root_ns, aafs_mnt->mnt_root, ".policy",
aafs_mnt->mnt_root);
mutex_unlock(&root_ns->lock);