From: Alexey Gladkov <gladkov.alexey@gmail.com> To: LKML <linux-kernel@vger.kernel.org>, io-uring@vger.kernel.org, Kernel Hardening <kernel-hardening@lists.openwall.com>, Linux Containers <containers@lists.linux-foundation.org>, linux-mm@kvack.org Cc: Jens Axboe <axboe@kernel.dk>, Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>, Linus Torvalds <torvalds@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, "Eric W . Biederman" <ebiederm@xmission.com>, Andrew Morton <akpm@linux-foundation.org>, Alexey Gladkov <legion@kernel.org> Subject: [PATCH v6 4/7] Reimplement RLIMIT_MSGQUEUE on top of ucounts Date: Mon, 15 Feb 2021 13:41:11 +0100 [thread overview] Message-ID: <8a3c7bc4c0f45d9b8313ef395f3fa180eef01d67.1613392826.git.gladkov.alexey@gmail.com> (raw) In-Reply-To: <cover.1613392826.git.gladkov.alexey@gmail.com> The rlimit counter is tied to uid in the user_namespace. This allows rlimit values to be specified in userns even if they are already globally exceeded by the user. However, the value of the previous user_namespaces cannot be exceeded. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> --- include/linux/sched/user.h | 4 ---- include/linux/user_namespace.h | 1 + ipc/mqueue.c | 29 +++++++++++++++-------------- kernel/fork.c | 1 + kernel/ucount.c | 1 + kernel/user_namespace.c | 1 + 6 files changed, 19 insertions(+), 18 deletions(-) diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index d33d867ad6c1..8a34446681aa 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -18,10 +18,6 @@ struct user_struct { #endif #ifdef CONFIG_EPOLL atomic_long_t epoll_watches; /* The number of file descriptors currently watched */ -#endif -#ifdef CONFIG_POSIX_MQUEUE - /* protected by mq_lock */ - unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */ #endif unsigned long locked_shm; /* How many pages of mlocked shm ? */ unsigned long unix_inflight; /* How many files in flight in unix sockets */ diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 0a27cd049404..52453143fe23 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -51,6 +51,7 @@ enum ucount_type { UCOUNT_INOTIFY_WATCHES, #endif UCOUNT_RLIMIT_NPROC, + UCOUNT_RLIMIT_MSGQUEUE, UCOUNT_COUNTS, }; diff --git a/ipc/mqueue.c b/ipc/mqueue.c index beff0cfcd1e8..05fcf067131f 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; @@ -309,6 +308,8 @@ static struct inode *mqueue_get_inode(struct super_block *sb, if (S_ISREG(mode)) { struct mqueue_inode_info *info; unsigned long mq_bytes, mq_treesize; + struct ucounts *ucounts; + bool overlimit; inode->i_fop = &mqueue_file_operations; inode->i_size = FILENT_SIZE; @@ -321,7 +322,7 @@ 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 +372,19 @@ static struct inode *mqueue_get_inode(struct super_block *sb, if (mq_bytes + mq_treesize < mq_bytes) goto out_inode; mq_bytes += mq_treesize; + ucounts = current_ucounts(); spin_lock(&mq_lock); - if (u->mq_bytes + mq_bytes < u->mq_bytes || - u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { + overlimit = inc_rlimit_ucounts_and_test(ucounts, UCOUNT_RLIMIT_MSGQUEUE, + mq_bytes, rlimit(RLIMIT_MSGQUEUE)); + if (overlimit) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); 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); + info->ucounts = get_ucounts(ucounts); } else if (S_ISDIR(mode)) { inc_nlink(inode); /* Some things misbehave if size == 0 on a directory */ @@ -497,7 +498,7 @@ 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 ucounts *ucounts; struct ipc_namespace *ipc_ns; struct msg_msg *msg, *nmsg; LIST_HEAD(tmp_msg); @@ -520,8 +521,8 @@ static void mqueue_evict_inode(struct inode *inode) free_msg(msg); } - user = info->user; - if (user) { + ucounts = info->ucounts; + if (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(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 +544,7 @@ 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(ucounts); } if (ipc_ns) put_ipc_ns(ipc_ns); diff --git a/kernel/fork.c b/kernel/fork.c index 812b023ecdce..0a939332efcc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -823,6 +823,7 @@ void __init fork_init(void) init_user_ns.ucount_max[i] = max_threads/2; init_user_ns.ucount_max[UCOUNT_RLIMIT_NPROC] = task_rlimit(&init_task, RLIMIT_NPROC); + init_user_ns.ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = task_rlimit(&init_task, RLIMIT_MSGQUEUE); #ifdef CONFIG_VMAP_STACK cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", diff --git a/kernel/ucount.c b/kernel/ucount.c index 2f42d2ee6e27..6fb2ebdef0bc 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -81,6 +81,7 @@ static struct ctl_table user_table[] = { UCOUNT_ENTRY("max_inotify_instances"), UCOUNT_ENTRY("max_inotify_watches"), #endif + { }, { }, { } }; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 2434b13b02e5..cc90d5203acf 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -122,6 +122,7 @@ int create_user_ns(struct cred *new) ns->ucount_max[i] = INT_MAX; } ns->ucount_max[UCOUNT_RLIMIT_NPROC] = rlimit(RLIMIT_NPROC); + ns->ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = rlimit(RLIMIT_MSGQUEUE); ns->ucounts = ucounts; /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */ -- 2.29.2 _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/containers
WARNING: multiple messages have this Message-ID (diff)
From: Alexey Gladkov <gladkov.alexey@gmail.com> To: LKML <linux-kernel@vger.kernel.org>, io-uring@vger.kernel.org, Kernel Hardening <kernel-hardening@lists.openwall.com>, Linux Containers <containers@lists.linux-foundation.org>, linux-mm@kvack.org Cc: Alexey Gladkov <legion@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Christian Brauner <christian.brauner@ubuntu.com>, "Eric W . Biederman" <ebiederm@xmission.com>, Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>, Kees Cook <keescook@chromium.org>, Linus Torvalds <torvalds@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com> Subject: [PATCH v6 4/7] Reimplement RLIMIT_MSGQUEUE on top of ucounts Date: Mon, 15 Feb 2021 13:41:11 +0100 [thread overview] Message-ID: <8a3c7bc4c0f45d9b8313ef395f3fa180eef01d67.1613392826.git.gladkov.alexey@gmail.com> (raw) In-Reply-To: <cover.1613392826.git.gladkov.alexey@gmail.com> The rlimit counter is tied to uid in the user_namespace. This allows rlimit values to be specified in userns even if they are already globally exceeded by the user. However, the value of the previous user_namespaces cannot be exceeded. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> --- include/linux/sched/user.h | 4 ---- include/linux/user_namespace.h | 1 + ipc/mqueue.c | 29 +++++++++++++++-------------- kernel/fork.c | 1 + kernel/ucount.c | 1 + kernel/user_namespace.c | 1 + 6 files changed, 19 insertions(+), 18 deletions(-) diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index d33d867ad6c1..8a34446681aa 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -18,10 +18,6 @@ struct user_struct { #endif #ifdef CONFIG_EPOLL atomic_long_t epoll_watches; /* The number of file descriptors currently watched */ -#endif -#ifdef CONFIG_POSIX_MQUEUE - /* protected by mq_lock */ - unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */ #endif unsigned long locked_shm; /* How many pages of mlocked shm ? */ unsigned long unix_inflight; /* How many files in flight in unix sockets */ diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 0a27cd049404..52453143fe23 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -51,6 +51,7 @@ enum ucount_type { UCOUNT_INOTIFY_WATCHES, #endif UCOUNT_RLIMIT_NPROC, + UCOUNT_RLIMIT_MSGQUEUE, UCOUNT_COUNTS, }; diff --git a/ipc/mqueue.c b/ipc/mqueue.c index beff0cfcd1e8..05fcf067131f 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; @@ -309,6 +308,8 @@ static struct inode *mqueue_get_inode(struct super_block *sb, if (S_ISREG(mode)) { struct mqueue_inode_info *info; unsigned long mq_bytes, mq_treesize; + struct ucounts *ucounts; + bool overlimit; inode->i_fop = &mqueue_file_operations; inode->i_size = FILENT_SIZE; @@ -321,7 +322,7 @@ 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 +372,19 @@ static struct inode *mqueue_get_inode(struct super_block *sb, if (mq_bytes + mq_treesize < mq_bytes) goto out_inode; mq_bytes += mq_treesize; + ucounts = current_ucounts(); spin_lock(&mq_lock); - if (u->mq_bytes + mq_bytes < u->mq_bytes || - u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { + overlimit = inc_rlimit_ucounts_and_test(ucounts, UCOUNT_RLIMIT_MSGQUEUE, + mq_bytes, rlimit(RLIMIT_MSGQUEUE)); + if (overlimit) { + dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); 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); + info->ucounts = get_ucounts(ucounts); } else if (S_ISDIR(mode)) { inc_nlink(inode); /* Some things misbehave if size == 0 on a directory */ @@ -497,7 +498,7 @@ 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 ucounts *ucounts; struct ipc_namespace *ipc_ns; struct msg_msg *msg, *nmsg; LIST_HEAD(tmp_msg); @@ -520,8 +521,8 @@ static void mqueue_evict_inode(struct inode *inode) free_msg(msg); } - user = info->user; - if (user) { + ucounts = info->ucounts; + if (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(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 +544,7 @@ 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(ucounts); } if (ipc_ns) put_ipc_ns(ipc_ns); diff --git a/kernel/fork.c b/kernel/fork.c index 812b023ecdce..0a939332efcc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -823,6 +823,7 @@ void __init fork_init(void) init_user_ns.ucount_max[i] = max_threads/2; init_user_ns.ucount_max[UCOUNT_RLIMIT_NPROC] = task_rlimit(&init_task, RLIMIT_NPROC); + init_user_ns.ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = task_rlimit(&init_task, RLIMIT_MSGQUEUE); #ifdef CONFIG_VMAP_STACK cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", diff --git a/kernel/ucount.c b/kernel/ucount.c index 2f42d2ee6e27..6fb2ebdef0bc 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -81,6 +81,7 @@ static struct ctl_table user_table[] = { UCOUNT_ENTRY("max_inotify_instances"), UCOUNT_ENTRY("max_inotify_watches"), #endif + { }, { }, { } }; diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 2434b13b02e5..cc90d5203acf 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -122,6 +122,7 @@ int create_user_ns(struct cred *new) ns->ucount_max[i] = INT_MAX; } ns->ucount_max[UCOUNT_RLIMIT_NPROC] = rlimit(RLIMIT_NPROC); + ns->ucount_max[UCOUNT_RLIMIT_MSGQUEUE] = rlimit(RLIMIT_MSGQUEUE); ns->ucounts = ucounts; /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */ -- 2.29.2
next prev parent reply other threads:[~2021-02-15 12:42 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-15 12:41 [PATCH v6 0/7] Count rlimits in each user namespace Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-15 12:41 ` [PATCH v6 1/7] Increase size of ucounts to atomic_long_t Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-15 12:41 ` [PATCH v6 2/7] Add a reference to ucounts for each cred Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-15 12:41 ` [PATCH v6 3/7] Reimplement RLIMIT_NPROC on top of ucounts Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-21 23:38 ` Jens Axboe 2021-02-21 23:38 ` Jens Axboe 2021-02-22 10:11 ` Alexey Gladkov 2021-02-22 10:11 ` Alexey Gladkov 2021-02-22 14:09 ` Jens Axboe 2021-02-22 14:09 ` Jens Axboe 2021-02-15 12:41 ` Alexey Gladkov [this message] 2021-02-15 12:41 ` [PATCH v6 4/7] Reimplement RLIMIT_MSGQUEUE " Alexey Gladkov 2021-02-15 12:41 ` [PATCH v6 5/7] Reimplement RLIMIT_SIGPENDING " Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-15 12:41 ` [PATCH v6 6/7] Reimplement RLIMIT_MEMLOCK " Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-15 15:09 ` kernel test robot 2021-02-15 15:09 ` kernel test robot 2021-02-15 15:09 ` kernel test robot 2021-02-15 17:49 ` kernel test robot 2021-02-15 17:49 ` kernel test robot 2021-02-15 17:49 ` kernel test robot 2021-02-16 11:12 ` [PATCH v7 " Alexey Gladkov 2021-02-16 11:12 ` Alexey Gladkov 2021-02-17 16:07 ` f009495a8d: BUG:KASAN:use-after-free_in_user_shm_unlock kernel test robot 2021-02-17 16:07 ` kernel test robot 2021-02-17 16:07 ` kernel test robot 2021-02-15 12:41 ` [PATCH v6 7/7] kselftests: Add test to check for rlimit changes in different user namespaces Alexey Gladkov 2021-02-15 12:41 ` Alexey Gladkov 2021-02-21 22:20 ` [PATCH v6 0/7] Count rlimits in each user namespace Linus Torvalds 2021-02-21 22:20 ` Linus Torvalds 2021-02-21 22:20 ` Linus Torvalds 2021-02-22 10:27 ` Alexey Gladkov 2021-02-22 10:27 ` Alexey Gladkov 2021-02-23 5:30 ` Eric W. Biederman 2021-02-23 5:30 ` Eric W. Biederman 2021-02-23 5:30 ` Eric W. Biederman
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