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authorLinus Torvalds <torvalds@linux-foundation.org>2021-06-28 20:39:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-28 20:39:26 -0700
commitc54b245d011855ea91c5beff07f1db74143ce614 (patch)
tree7982f28c76f578997f342c7255e222dabeffde63 /ipc
parente17c120f48f7d86ed9fd6e44e9436d32997fd9ec (diff)
parent5e6b8a50a7cec5686ee2c4bda1d49899c79a7eae (diff)
downloadlwn-c54b245d011855ea91c5beff07f1db74143ce614.tar.gz
lwn-c54b245d011855ea91c5beff07f1db74143ce614.zip
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace rlimit handling update from Eric Biederman: "This is the work mainly by Alexey Gladkov to limit rlimits to the rlimits of the user that created a user namespace, and to allow users to have stricter limits on the resources created within a user namespace." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: cred: add missing return error code when set_cred_ucounts() failed ucounts: Silence warning in dec_rlimit_ucounts ucounts: Set ucount_max to the largest positive value the type can hold kselftests: Add test to check for rlimit changes in different user namespaces Reimplement RLIMIT_MEMLOCK on top of ucounts Reimplement RLIMIT_SIGPENDING on top of ucounts Reimplement RLIMIT_MSGQUEUE on top of ucounts Reimplement RLIMIT_NPROC on top of ucounts Use atomic_t for ucounts reference counting Add a reference to ucounts for each cred Increase size of ucounts to atomic_long_t
Diffstat (limited to 'ipc')
-rw-r--r--ipc/mqueue.c40
-rw-r--r--ipc/shm.c26
2 files changed, 34 insertions, 32 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 4e4e61111500..5becca9be867 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -144,7 +144,7 @@ struct mqueue_inode_info {
struct pid *notify_owner;
u32 notify_self_exec_id;
struct user_namespace *notify_user_ns;
- struct user_struct *user; /* user who created, for accounting */
+ struct ucounts *ucounts; /* user who created, for accounting */
struct sock *notify_sock;
struct sk_buff *notify_cookie;
@@ -292,7 +292,6 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
struct ipc_namespace *ipc_ns, umode_t mode,
struct mq_attr *attr)
{
- struct user_struct *u = current_user();
struct inode *inode;
int ret = -ENOMEM;
@@ -321,7 +320,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
info->notify_owner = NULL;
info->notify_user_ns = NULL;
info->qsize = 0;
- info->user = NULL; /* set when all is ok */
+ info->ucounts = NULL; /* set when all is ok */
info->msg_tree = RB_ROOT;
info->msg_tree_rightmost = NULL;
info->node_cache = NULL;
@@ -371,19 +370,23 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
if (mq_bytes + mq_treesize < mq_bytes)
goto out_inode;
mq_bytes += mq_treesize;
- spin_lock(&mq_lock);
- if (u->mq_bytes + mq_bytes < u->mq_bytes ||
- u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
+ info->ucounts = get_ucounts(current_ucounts());
+ if (info->ucounts) {
+ long msgqueue;
+
+ spin_lock(&mq_lock);
+ msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
+ if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) {
+ dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
+ spin_unlock(&mq_lock);
+ put_ucounts(info->ucounts);
+ info->ucounts = NULL;
+ /* mqueue_evict_inode() releases info->messages */
+ ret = -EMFILE;
+ goto out_inode;
+ }
spin_unlock(&mq_lock);
- /* mqueue_evict_inode() releases info->messages */
- ret = -EMFILE;
- goto out_inode;
}
- u->mq_bytes += mq_bytes;
- spin_unlock(&mq_lock);
-
- /* all is ok */
- info->user = get_uid(u);
} else if (S_ISDIR(mode)) {
inc_nlink(inode);
/* Some things misbehave if size == 0 on a directory */
@@ -497,7 +500,6 @@ static void mqueue_free_inode(struct inode *inode)
static void mqueue_evict_inode(struct inode *inode)
{
struct mqueue_inode_info *info;
- struct user_struct *user;
struct ipc_namespace *ipc_ns;
struct msg_msg *msg, *nmsg;
LIST_HEAD(tmp_msg);
@@ -520,8 +522,7 @@ static void mqueue_evict_inode(struct inode *inode)
free_msg(msg);
}
- user = info->user;
- if (user) {
+ if (info->ucounts) {
unsigned long mq_bytes, mq_treesize;
/* Total amount of bytes accounted for the mqueue */
@@ -533,7 +534,7 @@ static void mqueue_evict_inode(struct inode *inode)
info->attr.mq_msgsize);
spin_lock(&mq_lock);
- user->mq_bytes -= mq_bytes;
+ dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
/*
* get_ns_from_inode() ensures that the
* (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
@@ -543,7 +544,8 @@ static void mqueue_evict_inode(struct inode *inode)
if (ipc_ns)
ipc_ns->mq_queues_count--;
spin_unlock(&mq_lock);
- free_uid(user);
+ put_ucounts(info->ucounts);
+ info->ucounts = NULL;
}
if (ipc_ns)
put_ipc_ns(ipc_ns);
diff --git a/ipc/shm.c b/ipc/shm.c
index febd88daba8c..003234fbbd17 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -60,7 +60,7 @@ struct shmid_kernel /* private to the kernel */
time64_t shm_ctim;
struct pid *shm_cprid;
struct pid *shm_lprid;
- struct user_struct *mlock_user;
+ struct ucounts *mlock_ucounts;
/* The task created the shm object. NULL if the task is dead. */
struct task_struct *shm_creator;
@@ -286,10 +286,10 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
shm_rmid(ns, shp);
shm_unlock(shp);
if (!is_file_hugepages(shm_file))
- shmem_lock(shm_file, 0, shp->mlock_user);
- else if (shp->mlock_user)
+ shmem_lock(shm_file, 0, shp->mlock_ucounts);
+ else if (shp->mlock_ucounts)
user_shm_unlock(i_size_read(file_inode(shm_file)),
- shp->mlock_user);
+ shp->mlock_ucounts);
fput(shm_file);
ipc_update_pid(&shp->shm_cprid, NULL);
ipc_update_pid(&shp->shm_lprid, NULL);
@@ -625,7 +625,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
shp->shm_perm.key = key;
shp->shm_perm.mode = (shmflg & S_IRWXUGO);
- shp->mlock_user = NULL;
+ shp->mlock_ucounts = NULL;
shp->shm_perm.security = NULL;
error = security_shm_alloc(&shp->shm_perm);
@@ -650,7 +650,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
if (shmflg & SHM_NORESERVE)
acctflag = VM_NORESERVE;
file = hugetlb_file_setup(name, hugesize, acctflag,
- &shp->mlock_user, HUGETLB_SHMFS_INODE,
+ &shp->mlock_ucounts, HUGETLB_SHMFS_INODE,
(shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
} else {
/*
@@ -698,8 +698,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
no_id:
ipc_update_pid(&shp->shm_cprid, NULL);
ipc_update_pid(&shp->shm_lprid, NULL);
- if (is_file_hugepages(file) && shp->mlock_user)
- user_shm_unlock(size, shp->mlock_user);
+ if (is_file_hugepages(file) && shp->mlock_ucounts)
+ user_shm_unlock(size, shp->mlock_ucounts);
fput(file);
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
return error;
@@ -1105,12 +1105,12 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
goto out_unlock0;
if (cmd == SHM_LOCK) {
- struct user_struct *user = current_user();
+ struct ucounts *ucounts = current_ucounts();
- err = shmem_lock(shm_file, 1, user);
+ err = shmem_lock(shm_file, 1, ucounts);
if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
shp->shm_perm.mode |= SHM_LOCKED;
- shp->mlock_user = user;
+ shp->mlock_ucounts = ucounts;
}
goto out_unlock0;
}
@@ -1118,9 +1118,9 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
/* SHM_UNLOCK */
if (!(shp->shm_perm.mode & SHM_LOCKED))
goto out_unlock0;
- shmem_lock(shm_file, 0, shp->mlock_user);
+ shmem_lock(shm_file, 0, shp->mlock_ucounts);
shp->shm_perm.mode &= ~SHM_LOCKED;
- shp->mlock_user = NULL;
+ shp->mlock_ucounts = NULL;
get_file(shm_file);
ipc_unlock_object(&shp->shm_perm);
rcu_read_unlock();