diff options
| author | Waiman Long <longman@redhat.com> | 2018-03-15 10:45:09 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2018-03-15 10:45:09 +1100 |
| commit | b587a576e9f7f59c4005058f6aafe2820913c6b3 (patch) | |
| tree | 2ebf672333b3b7b49e8a6c3879e0bee074698ec6 /ipc | |
| parent | 69acf62ba3a9dd9394489d38e1715f0e5b0cb433 (diff) | |
| download | linux-next-b587a576e9f7f59c4005058f6aafe2820913c6b3.tar.gz | |
ipc/: clamp semmni to the real IPCMNI limit
Clamp the semmni value (fourth element of sem_ctls[] array) to within the
[0, IPCMNI] range and prints a warning message once when an out-of-range
value is being written.
Link: http://lkml.kernel.org/r/1520885744-1546-6-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/ipc_sysctl.c | 13 | ||||
| -rw-r--r-- | ipc/sem.c | 28 | ||||
| -rw-r--r-- | ipc/util.h | 4 |
3 files changed, 44 insertions, 1 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 1955dd4e34c3..49cbc439ad41 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -88,12 +88,22 @@ 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 = proc_ipc_dointvec(table, write, buffer, lenp, ppos); + + sem_check_semmni(table, current->nsproxy->ipc_ns); + 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; @@ -177,7 +187,8 @@ 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, + .flags = CTL_FLAGS_CLAMP_RANGE, }, #ifdef CONFIG_CHECKPOINT_RESTORE { diff --git a/ipc/sem.c b/ipc/sem.c index 79acad0e0aa1..852cfd4aef73 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2344,3 +2344,31 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it) return 0; } #endif + +#ifdef CONFIG_PROC_SYSCTL +/* + * Check to see if semmni is out of range and clamp it if necessary. + */ +void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns) +{ + bool clamped = false; + + if (!(table->flags & CTL_FLAGS_CLAMP_RANGE)) + return; + + /* + * Clamp semmni to the range [0, IPCMNI]. + */ + if (ns->sc_semmni < 0) { + ns->sc_semmni = 0; + clamped = true; + } + if (ns->sc_semmni > IPCMNI) { + ns->sc_semmni = IPCMNI; + clamped = true; + } + if (clamped) + pr_warn_once("sysctl: \"sem[3]\" was set out of range [%d, %d], clamped to %d.\n", + 0, IPCMNI, ns->sc_semmni); +} +#endif diff --git a/ipc/util.h b/ipc/util.h index 89b8ec176fc4..af5739497cbb 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -206,6 +206,10 @@ 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 *)); +#ifdef CONFIG_PROC_SYSCTL +extern void sem_check_semmni(struct ctl_table *table, struct ipc_namespace *ns); +#endif + #ifdef CONFIG_COMPAT #include <linux/compat.h> struct compat_ipc_perm { |