diff options
| -rw-r--r-- | fs/fuse/inode.c | 78 |
1 files changed, 72 insertions, 6 deletions
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 9aa6f46d0c32..e54ddbda208c 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -14,6 +14,7 @@ #include <linux/seq_file.h> #include <linux/init.h> #include <linux/module.h> +#include <linux/moduleparam.h> #include <linux/parser.h> #include <linux/statfs.h> #include <linux/random.h> @@ -28,6 +29,24 @@ static struct kmem_cache *fuse_inode_cachep; struct list_head fuse_conn_list; DEFINE_MUTEX(fuse_mutex); +static int set_global_limit(const char *val, struct kernel_param *kp); + +static unsigned max_user_bgreq; +module_param_call(max_user_bgreq, set_global_limit, param_get_uint, + &max_user_bgreq, 0644); +__MODULE_PARM_TYPE(max_user_bgreq, "uint"); +MODULE_PARM_DESC(max_user_bgreq, + "Global limit for the maximum number of backgrounded requests an " + "unprivileged user can set"); + +static unsigned max_user_congthresh; +module_param_call(max_user_congthresh, set_global_limit, param_get_uint, + &max_user_congthresh, 0644); +__MODULE_PARM_TYPE(max_user_congthresh, "uint"); +MODULE_PARM_DESC(max_user_congthresh, + "Global limit for the maximum congestion threshold an " + "unprivileged user can set"); + #define FUSE_SUPER_MAGIC 0x65735546 #define FUSE_DEFAULT_BLKSIZE 512 @@ -735,6 +754,54 @@ static const struct super_operations fuse_super_operations = { .show_options = fuse_show_options, }; +static void sanitize_global_limit(unsigned *limit) +{ + if (*limit == 0) + *limit = ((num_physpages << PAGE_SHIFT) >> 13) / + sizeof(struct fuse_req); + + if (*limit >= 1 << 16) + *limit = (1 << 16) - 1; +} + +static int set_global_limit(const char *val, struct kernel_param *kp) +{ + int rv; + + rv = param_set_uint(val, kp); + if (rv) + return rv; + + sanitize_global_limit((unsigned *)kp->arg); + + return 0; +} + +static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) +{ + int cap_sys_admin = capable(CAP_SYS_ADMIN); + + if (arg->minor < 13) + return; + + sanitize_global_limit(&max_user_bgreq); + sanitize_global_limit(&max_user_congthresh); + + if (arg->max_background) { + fc->max_background = arg->max_background; + + if (!cap_sys_admin && fc->max_background > max_user_bgreq) + fc->max_background = max_user_bgreq; + } + if (arg->congestion_threshold) { + fc->congestion_threshold = arg->congestion_threshold; + + if (!cap_sys_admin && + fc->congestion_threshold > max_user_congthresh) + fc->congestion_threshold = max_user_congthresh; + } +} + static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) { struct fuse_init_out *arg = &req->misc.init_out; @@ -744,12 +811,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) else { unsigned long ra_pages; - if (arg->minor >= 13) { - if (arg->max_background) - fc->max_background = arg->max_background; - if (arg->congestion_threshold) - fc->congestion_threshold = arg->congestion_threshold; - } + process_init_limits(fc, arg); + if (arg->minor >= 6) { ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; if (arg->flags & FUSE_ASYNC_READ) @@ -1161,6 +1224,9 @@ static int __init fuse_init(void) if (res) goto err_sysfs_cleanup; + sanitize_global_limit(&max_user_bgreq); + sanitize_global_limit(&max_user_congthresh); + return 0; err_sysfs_cleanup: |