diff options
| author | Waiman Long <longman@redhat.com> | 2018-10-30 15:07:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-10-31 08:54:14 -0700 |
| commit | 8c81ddd2acd2c10979f5a64f6784ce7c6717495e (patch) | |
| tree | 753eefd7695e89bd0667bb877123be642c134642 | |
| parent | 6730e6580177d13f4612767873cb5a533ad63c61 (diff) | |
| download | linux-8c81ddd2acd2c10979f5a64f6784ce7c6717495e.tar.bz2 | |
ipc: IPCMNI limit check for semmni
For SysV semaphores, the semmni value is the last part of the 4-element
sem number array. To make semmni behave in a similar way to msgmni and
shmmni, we can't directly use the _minmax handler. Instead, a special sem
specific handler is added to check the last argument to make sure that it
is limited to the [0, IPCMNI] range. An error will be returned if this is
not the case.
Link: http://lkml.kernel.org/r/1536352137-12003-3-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | ipc/ipc_sysctl.c | 23 | ||||
| -rw-r--r-- | ipc/util.h | 9 |
2 files changed, 31 insertions, 1 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index f87cb29436ef..49f9bf4ffc7f 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -88,12 +88,33 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); } +static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int ret, semmni; + struct ipc_namespace *ns = current->nsproxy->ipc_ns; + + semmni = ns->sem_ctls[3]; + ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos); + + if (!ret) + ret = sem_check_semmni(current->nsproxy->ipc_ns); + + /* + * Reset the semmni value if an error happens. + */ + if (ret) + ns->sem_ctls[3] = semmni; + return ret; +} + #else #define proc_ipc_doulongvec_minmax NULL #define proc_ipc_dointvec NULL #define proc_ipc_dointvec_minmax NULL #define proc_ipc_dointvec_minmax_orphans NULL #define proc_ipc_auto_msgmni NULL +#define proc_ipc_sem_dointvec NULL #endif static int zero; @@ -175,7 +196,7 @@ static struct ctl_table ipc_kern_table[] = { .data = &init_ipc_ns.sem_ctls, .maxlen = 4*sizeof(int), .mode = 0644, - .proc_handler = proc_ipc_dointvec, + .proc_handler = proc_ipc_sem_dointvec, }, #ifdef CONFIG_CHECKPOINT_RESTORE { diff --git a/ipc/util.h b/ipc/util.h index 1ee81bce25e9..d768fdbed515 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -217,6 +217,15 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); +static inline int sem_check_semmni(struct ipc_namespace *ns) { + /* + * Check semmni range [0, IPCMNI] + * semmni is the last element of sem_ctls[4] array + */ + return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI)) + ? -ERANGE : 0; +} + #ifdef CONFIG_COMPAT #include <linux/compat.h> struct compat_ipc_perm { |