diff options
| -rw-r--r-- | fs/proc/base.c | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index aa50d1ac28fc..60c71b10eaee 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1836,8 +1836,6 @@ end_instantiate: return dir_emit(ctx, name, len, 1, DT_UNKNOWN); } -#ifdef CONFIG_CHECKPOINT_RESTORE - /* * dname_to_vma_addr - maps a dentry name into two unsigned longs * which represent vma start and end addresses. @@ -1864,11 +1862,6 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags) if (flags & LOOKUP_RCU) return -ECHILD; - if (!capable(CAP_SYS_ADMIN)) { - status = -EPERM; - goto out_notask; - } - inode = d_inode(dentry); task = get_proc_task(inode); if (!task) @@ -1957,6 +1950,29 @@ struct map_files_info { unsigned char name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */ }; +/* + * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the + * symlinks may be used to bypass permissions on ancestor directories in the + * path to the file in question. + */ +static const char * +proc_map_files_follow_link(struct dentry *dentry, void **cookie) +{ + if (!capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + + return proc_pid_follow_link(dentry, NULL); +} + +/* + * Identical to proc_pid_link_inode_operations except for follow_link() + */ +static const struct inode_operations proc_map_files_link_inode_operations = { + .readlink = proc_pid_readlink, + .follow_link = proc_map_files_follow_link, + .setattr = proc_setattr, +}; + static int proc_map_files_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) @@ -1972,7 +1988,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry, ei = PROC_I(inode); ei->op.proc_get_link = proc_map_files_get_link; - inode->i_op = &proc_pid_link_inode_operations; + inode->i_op = &proc_map_files_link_inode_operations; inode->i_size = 64; inode->i_mode = S_IFLNK; @@ -1996,10 +2012,6 @@ static struct dentry *proc_map_files_lookup(struct inode *dir, int result; struct mm_struct *mm; - result = -EPERM; - if (!capable(CAP_SYS_ADMIN)) - goto out; - result = -ENOENT; task = get_proc_task(dir); if (!task) @@ -2053,10 +2065,6 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx) struct map_files_info *p; int ret; - ret = -EPERM; - if (!capable(CAP_SYS_ADMIN)) - goto out; - ret = -ENOENT; task = get_proc_task(file_inode(file)); if (!task) @@ -2245,7 +2253,6 @@ static const struct file_operations proc_timers_operations = { .llseek = seq_lseek, .release = seq_release_private, }; -#endif /* CONFIG_CHECKPOINT_RESTORE */ static int proc_pident_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) @@ -2744,9 +2751,7 @@ static const struct inode_operations proc_task_inode_operations; static const struct pid_entry tgid_base_stuff[] = { DIR("task", S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations), DIR("fd", S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations), -#ifdef CONFIG_CHECKPOINT_RESTORE DIR("map_files", S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations), -#endif DIR("fdinfo", S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations), DIR("ns", S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations), #ifdef CONFIG_NET |