lkml.org 
[lkml]   [2018]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 6/6] ipc: Clamp semmni to the real IPCMNI limit
    Date
    This patch clamps 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.

    Signed-off-by: Waiman Long <longman@redhat.com>
    ---
    ipc/ipc_sysctl.c | 13 ++++++++++++-
    ipc/sem.c | 28 ++++++++++++++++++++++++++++
    ipc/util.h | 4 ++++
    3 files changed, 44 insertions(+), 1 deletion(-)

    diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
    index 8eb7268..2c03f57 100644
    --- a/ipc/ipc_sysctl.c
    +++ b/ipc/ipc_sysctl.c
    @@ -97,12 +97,22 @@ 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;
    @@ -186,7 +196,8 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
    .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 a4af049..739dfca 100644
    --- a/ipc/sem.c
    +++ b/ipc/sem.c
    @@ -2337,3 +2337,31 @@ 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("Kernel parameter \"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 89b8ec1..af57394 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 {
    --
    1.8.3.1
    \
     
     \ /
      Last update: 2018-03-01 18:46    [W:5.200 / U:0.000 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site