From 5563cabdde7ee53c34ec7e5e0283bfcc9a1bc893 Mon Sep 17 00:00:00 2001 From: Michal Clapinski Date: Mon, 8 Nov 2021 18:35:59 -0800 Subject: 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 Reviewed-by: Davidlohr Bueso Reviewed-by: Manfred Spraul Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/ipc_sysctl.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) (limited to 'ipc/ipc_sysctl.c') 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 #include #include +#include #include #include #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, }, -- cgit v1.2.3 From 0e9beb8a96f21a6df1579cb3a679e150e3269d80 Mon Sep 17 00:00:00 2001 From: Manfred Spraul Date: Mon, 8 Nov 2021 18:36:02 -0800 Subject: ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL Compilation of ipc/ipc_sysctl.c is controlled by obj-$(CONFIG_SYSVIPC_SYSCTL) [see ipc/Makefile] And CONFIG_SYSVIPC_SYSCTL depends on SYSCTL [see init/Kconfig] An SYSCTL is selected by PROC_SYSCTL. [see fs/proc/Kconfig] Thus: #ifndef CONFIG_PROC_SYSCTL in ipc/ipc_sysctl.c is impossible, the fallback can be removed. Link: https://lkml.kernel.org/r/20210918145337.3369-1-manfred@colorfullife.com Signed-off-by: Manfred Spraul Reviewed-by: "Eric W. Biederman" Acked-by: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/ipc_sysctl.c | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'ipc/ipc_sysctl.c') diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 345e4d673e61..f101c171753f 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c @@ -23,7 +23,6 @@ static void *get_ipc(struct ctl_table *table) return which; } -#ifdef CONFIG_PROC_SYSCTL static int proc_ipc_dointvec(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -118,18 +117,6 @@ static int proc_ipc_dointvec_minmax_checkpoint_restore(struct ctl_table *table, } #endif -#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 -#ifdef CONFIG_CHECKPOINT_RESTORE -#define proc_ipc_dointvec_minmax_checkpoint_restore NULL -#endif /* CONFIG_CHECKPOINT_RESTORE */ -#endif - int ipc_mni = IPCMNI; int ipc_mni_shift = IPCMNI_SHIFT; int ipc_min_cycle = RADIX_TREE_MAP_SIZE; -- cgit v1.2.3