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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-03 19:15:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-03 19:15:32 -0700
commit17dec0a949153d9ac00760ba2f5b78cb583e995f (patch)
treeaaf44fee3aca81a86ecfa46f3f409d5cf5675f1f /ipc/shm.c
parentd92cd810e64aa7cf22b05f0ea1c7d3e8dbae75fe (diff)
parent2236d4d39035b9839944603ec4b65ce71180a9ea (diff)
Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman: "There was a lot of work this cycle fixing bugs that were discovered after the merge window and getting everything ready where we can reasonably support fully unprivileged fuse. The bug fixes you already have and much of the unprivileged fuse work is coming in via other trees. Still left for fully unprivileged fuse is figuring out how to cleanly handle .set_acl and .get_acl in the legacy case, and properly handling of evm xattrs on unprivileged mounts. Included in the tree is a cleanup from Alexely that replaced a linked list with a statically allocated fix sized array for the pid caches, which simplifies and speeds things up. Then there is are some cleanups and fixes for the ipc namespace. The motivation was that in reviewing other code it was discovered that access ipc objects from different pid namespaces recorded pids in such a way that when asked the wrong pids were returned. In the worst case there has been a measured 30% performance impact for sysvipc semaphores. Other test cases showed no measurable performance impact. Manfred Spraul and Davidlohr Bueso who tend to work on sysvipc performance both gave the nod that this is good enough. Casey Schaufler and James Morris have given their approval to the LSM side of the changes. I simplified the types and the code dealing with sysvipc to pass just kern_ipc_perm for all three types of ipc. Which reduced the header dependencies throughout the kernel and simplified the lsm code. Which let me work on the pid fixes without having to worry about trivial changes causing complete kernel recompiles" * 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ipc/shm: Fix pid freeing. ipc/shm: fix up for struct file no longer being available in shm.h ipc/smack: Tidy up from the change in type of the ipc security hooks ipc: Directly call the security hook in ipc_ops.associate ipc/sem: Fix semctl(..., GETPID, ...) between pid namespaces ipc/msg: Fix msgctl(..., IPC_STAT, ...) between pid namespaces ipc/shm: Fix shmctl(..., IPC_STAT, ...) between pid namespaces. ipc/util: Helpers for making the sysvipc operations pid namespace aware ipc: Move IPCMNI from include/ipc.h into ipc/util.h msg: Move struct msg_queue into ipc/msg.c shm: Move struct shmid_kernel into ipc/shm.c sem: Move struct sem and struct sem_array into ipc/sem.c msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooks shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooks sem/security: Pass kern_ipc_perm not sem_array into the sem security hooks pidns: simpler allocation of pid_* caches
Diffstat (limited to 'ipc/shm.c')
-rw-r--r--ipc/shm.c68
1 files changed, 42 insertions, 26 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index c38c8425a89e..acefe44fefef 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -48,6 +48,28 @@
#include "util.h"
+struct shmid_kernel /* private to the kernel */
+{
+ struct kern_ipc_perm shm_perm;
+ struct file *shm_file;
+ unsigned long shm_nattch;
+ unsigned long shm_segsz;
+ time64_t shm_atim;
+ time64_t shm_dtim;
+ time64_t shm_ctim;
+ struct pid *shm_cprid;
+ struct pid *shm_lprid;
+ struct user_struct *mlock_user;
+
+ /* The task created the shm object. NULL if the task is dead. */
+ struct task_struct *shm_creator;
+ struct list_head shm_clist; /* list by creator */
+} __randomize_layout;
+
+/* shm_mode upper byte flags */
+#define SHM_DEST 01000 /* segment will be destroyed on last detach */
+#define SHM_LOCKED 02000 /* segment will not be swapped */
+
struct shm_file_data {
int id;
struct ipc_namespace *ns;
@@ -181,7 +203,7 @@ static void shm_rcu_free(struct rcu_head *head)
rcu);
struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
shm_perm);
- security_shm_free(shp);
+ security_shm_free(&shp->shm_perm);
kvfree(shp);
}
@@ -204,7 +226,7 @@ static int __shm_open(struct vm_area_struct *vma)
return PTR_ERR(shp);
shp->shm_atim = ktime_get_real_seconds();
- shp->shm_lprid = task_tgid_vnr(current);
+ ipc_update_pid(&shp->shm_lprid, task_tgid(current));
shp->shm_nattch++;
shm_unlock(shp);
return 0;
@@ -245,6 +267,8 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
user_shm_unlock(i_size_read(file_inode(shm_file)),
shp->mlock_user);
fput(shm_file);
+ ipc_update_pid(&shp->shm_cprid, NULL);
+ ipc_update_pid(&shp->shm_lprid, NULL);
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
}
@@ -289,7 +313,7 @@ static void shm_close(struct vm_area_struct *vma)
if (WARN_ON_ONCE(IS_ERR(shp)))
goto done; /* no-op */
- shp->shm_lprid = task_tgid_vnr(current);
+ ipc_update_pid(&shp->shm_lprid, task_tgid(current));
shp->shm_dtim = ktime_get_real_seconds();
shp->shm_nattch--;
if (shm_may_destroy(ns, shp))
@@ -566,7 +590,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
shp->mlock_user = NULL;
shp->shm_perm.security = NULL;
- error = security_shm_alloc(shp);
+ error = security_shm_alloc(&shp->shm_perm);
if (error) {
kvfree(shp);
return error;
@@ -604,8 +628,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
if (IS_ERR(file))
goto no_file;
- shp->shm_cprid = task_tgid_vnr(current);
- shp->shm_lprid = 0;
+ shp->shm_cprid = get_pid(task_tgid(current));
+ shp->shm_lprid = NULL;
shp->shm_atim = shp->shm_dtim = 0;
shp->shm_ctim = ktime_get_real_seconds();
shp->shm_segsz = size;
@@ -634,6 +658,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
return error;
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);
fput(file);
@@ -645,17 +671,6 @@ no_file:
/*
* Called with shm_ids.rwsem and ipcp locked.
*/
-static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
-{
- struct shmid_kernel *shp;
-
- shp = container_of(ipcp, struct shmid_kernel, shm_perm);
- return security_shm_associate(shp, shmflg);
-}
-
-/*
- * Called with shm_ids.rwsem and ipcp locked.
- */
static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
{
@@ -673,7 +688,7 @@ long ksys_shmget(key_t key, size_t size, int shmflg)
struct ipc_namespace *ns;
static const struct ipc_ops shm_ops = {
.getnew = newseg,
- .associate = shm_security,
+ .associate = security_shm_associate,
.more_checks = shm_more_checks,
};
struct ipc_params shm_params;
@@ -852,7 +867,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
shp = container_of(ipcp, struct shmid_kernel, shm_perm);
- err = security_shm_shmctl(shp, cmd);
+ err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock1;
@@ -951,7 +966,7 @@ static int shmctl_stat(struct ipc_namespace *ns, int shmid,
if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
goto out_unlock;
- err = security_shm_shmctl(shp, cmd);
+ err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock;
@@ -968,8 +983,8 @@ static int shmctl_stat(struct ipc_namespace *ns, int shmid,
tbuf->shm_atime = shp->shm_atim;
tbuf->shm_dtime = shp->shm_dtim;
tbuf->shm_ctime = shp->shm_ctim;
- tbuf->shm_cpid = shp->shm_cprid;
- tbuf->shm_lpid = shp->shm_lprid;
+ tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
+ tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
tbuf->shm_nattch = shp->shm_nattch;
ipc_unlock_object(&shp->shm_perm);
@@ -995,7 +1010,7 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
}
audit_ipc_obj(&(shp->shm_perm));
- err = security_shm_shmctl(shp, cmd);
+ err = security_shm_shmctl(&shp->shm_perm, cmd);
if (err)
goto out_unlock1;
@@ -1375,7 +1390,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
if (ipcperms(ns, &shp->shm_perm, acc_mode))
goto out_unlock;
- err = security_shm_shmat(shp, shmaddr, shmflg);
+ err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
if (err)
goto out_unlock;
@@ -1618,6 +1633,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
{
+ struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
struct user_namespace *user_ns = seq_user_ns(s);
struct kern_ipc_perm *ipcp = it;
struct shmid_kernel *shp;
@@ -1640,8 +1656,8 @@ static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
shp->shm_perm.id,
shp->shm_perm.mode,
shp->shm_segsz,
- shp->shm_cprid,
- shp->shm_lprid,
+ pid_nr_ns(shp->shm_cprid, pid_ns),
+ pid_nr_ns(shp->shm_lprid, pid_ns),
shp->shm_nattch,
from_kuid_munged(user_ns, shp->shm_perm.uid),
from_kgid_munged(user_ns, shp->shm_perm.gid),