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| author | Michal Clapinski <mclapinski@google.com> | 2021-11-08 18:35:59 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-09 10:02:53 -0800 |
| commit | 5563cabdde7ee53c34ec7e5e0283bfcc9a1bc893 (patch) | |
| tree | 7aa5212a7c84ab3df319c71b15b511204e6a3b4d /ipc | |
| parent | 303f8e2d02002dbe331cab7813ee091aead3cd39 (diff) | |
| download | lwn-5563cabdde7ee53c34ec7e5e0283bfcc9a1bc893.tar.gz lwn-5563cabdde7ee53c34ec7e5e0283bfcc9a1bc893.zip | |
ipc: check checkpoint_restore_ns_capable() to modify C/R proc files
This commit removes the requirement to be root to modify sem_next_id,
msg_next_id and shm_next_id and checks checkpoint_restore_ns_capable
instead.
Since those files are specific to the IPC namespace, there is no reason
they should require root privileges. This is similar to ns_last_pid,
which also only checks checkpoint_restore_ns_capable.
[akpm@linux-foundation.org: ipc/ipc_sysctl.c needs capability.h for checkpoint_restore_ns_capable()]
Link: https://lkml.kernel.org/r/20210916163717.3179496-1-mclapinski@google.com
Signed-off-by: Michal Clapinski <mclapinski@google.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Manfred Spraul <manfred@colorfullife.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/ipc_sysctl.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 3f312bf2b116..345e4d673e61 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -10,6 +10,7 @@ #include <linux/nsproxy.h> #include <linux/sysctl.h> #include <linux/uaccess.h> +#include <linux/capability.h> #include <linux/ipc_namespace.h> #include <linux/msg.h> #include "util.h" @@ -104,6 +105,19 @@ static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, return ret; } +#ifdef CONFIG_CHECKPOINT_RESTORE +static int proc_ipc_dointvec_minmax_checkpoint_restore(struct ctl_table *table, + int write, void *buffer, size_t *lenp, loff_t *ppos) +{ + struct user_namespace *user_ns = current->nsproxy->ipc_ns->user_ns; + + if (write && !checkpoint_restore_ns_capable(user_ns)) + return -EPERM; + + return proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos); +} +#endif + #else #define proc_ipc_doulongvec_minmax NULL #define proc_ipc_dointvec NULL @@ -111,6 +125,9 @@ static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, #define proc_ipc_dointvec_minmax_orphans NULL #define proc_ipc_auto_msgmni NULL #define proc_ipc_sem_dointvec NULL +#ifdef CONFIG_CHECKPOINT_RESTORE +#define proc_ipc_dointvec_minmax_checkpoint_restore NULL +#endif /* CONFIG_CHECKPOINT_RESTORE */ #endif int ipc_mni = IPCMNI; @@ -198,8 +215,8 @@ static struct ctl_table ipc_kern_table[] = { .procname = "sem_next_id", .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id, .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id), - .mode = 0644, - .proc_handler = proc_ipc_dointvec_minmax, + .mode = 0666, + .proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_INT_MAX, }, @@ -207,8 +224,8 @@ static struct ctl_table ipc_kern_table[] = { .procname = "msg_next_id", .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id, .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id), - .mode = 0644, - .proc_handler = proc_ipc_dointvec_minmax, + .mode = 0666, + .proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_INT_MAX, }, @@ -216,8 +233,8 @@ static struct ctl_table ipc_kern_table[] = { .procname = "shm_next_id", .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id, .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id), - .mode = 0644, - .proc_handler = proc_ipc_dointvec_minmax, + .mode = 0666, + .proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_INT_MAX, }, |