diff options
Diffstat (limited to 'security/tomoyo/file.c')
| -rw-r--r-- | security/tomoyo/file.c | 121 |
1 files changed, 115 insertions, 6 deletions
diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c index ab0cd3538510..5ae3a571559f 100644 --- a/security/tomoyo/file.c +++ b/security/tomoyo/file.c @@ -14,21 +14,50 @@ #include "realpath.h" #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) -/* Structure for "allow_read" keyword. */ +/* + * tomoyo_globally_readable_file_entry is a structure which is used for holding + * "allow_read" entries. + * It has following fields. + * + * (1) "list" which is linked to tomoyo_globally_readable_list . + * (2) "filename" is a pathname which is allowed to open(O_RDONLY). + * (3) "is_deleted" is a bool which is true if marked as deleted, false + * otherwise. + */ struct tomoyo_globally_readable_file_entry { struct list_head list; const struct tomoyo_path_info *filename; bool is_deleted; }; -/* Structure for "file_pattern" keyword. */ +/* + * tomoyo_pattern_entry is a structure which is used for holding + * "tomoyo_pattern_list" entries. + * It has following fields. + * + * (1) "list" which is linked to tomoyo_pattern_list . + * (2) "pattern" is a pathname pattern which is used for converting pathnames + * to pathname patterns during learning mode. + * (3) "is_deleted" is a bool which is true if marked as deleted, false + * otherwise. + */ struct tomoyo_pattern_entry { struct list_head list; const struct tomoyo_path_info *pattern; bool is_deleted; }; -/* Structure for "deny_rewrite" keyword. */ +/* + * tomoyo_no_rewrite_entry is a structure which is used for holding + * "deny_rewrite" entries. + * It has following fields. + * + * (1) "list" which is linked to tomoyo_no_rewrite_list . + * (2) "pattern" is a pathname which is by default not permitted to modify + * already existing content. + * (3) "is_deleted" is a bool which is true if marked as deleted, false + * otherwise. + */ struct tomoyo_no_rewrite_entry { struct list_head list; const struct tomoyo_path_info *pattern; @@ -141,7 +170,31 @@ static int tomoyo_update_single_path_acl(const u8 type, const char *filename, struct tomoyo_domain_info * const domain, const bool is_delete); -/* The list for "struct tomoyo_globally_readable_file_entry". */ +/* + * tomoyo_globally_readable_list is used for holding list of pathnames which + * are by default allowed to be open()ed for reading by any process. + * + * An entry is added by + * + * # echo 'allow_read /lib/libc-2.5.so' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and is deleted by + * + * # echo 'delete allow_read /lib/libc-2.5.so' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and all entries are retrieved by + * + * # grep ^allow_read /sys/kernel/security/tomoyo/exception_policy + * + * In the example above, any process is allowed to + * open("/lib/libc-2.5.so", O_RDONLY). + * One exception is, if the domain which current process belongs to is marked + * as "ignore_global_allow_read", current process can't do so unless explicitly + * given "allow_read /lib/libc-2.5.so" to the domain which current process + * belongs to. + */ static LIST_HEAD(tomoyo_globally_readable_list); static DECLARE_RWSEM(tomoyo_globally_readable_list_lock); @@ -256,7 +309,35 @@ bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head) return done; } -/* The list for "struct tomoyo_pattern_entry". */ +/* tomoyo_pattern_list is used for holding list of pathnames which are used for + * converting pathnames to pathname patterns during learning mode. + * + * An entry is added by + * + * # echo 'file_pattern /proc/\$/mounts' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and is deleted by + * + * # echo 'delete file_pattern /proc/\$/mounts' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and all entries are retrieved by + * + * # grep ^file_pattern /sys/kernel/security/tomoyo/exception_policy + * + * In the example above, if a process which belongs to a domain which is in + * learning mode requested open("/proc/1/mounts", O_RDONLY), + * "allow_read /proc/\$/mounts" is automatically added to the domain which that + * process belongs to. + * + * It is not a desirable behavior that we have to use /proc/\$/ instead of + * /proc/self/ when current process needs to access only current process's + * information. As of now, LSM version of TOMOYO is using __d_path() for + * calculating pathname. Non LSM version of TOMOYO is using its own function + * which pretends as if /proc/self/ is not a symlink; so that we can forbid + * current process from accessing other process's information. + */ static LIST_HEAD(tomoyo_pattern_list); static DECLARE_RWSEM(tomoyo_pattern_list_lock); @@ -377,7 +458,35 @@ bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head) return done; } -/* The list for "struct tomoyo_no_rewrite_entry". */ +/* + * tomoyo_no_rewrite_list is used for holding list of pathnames which are by + * default forbidden to modify already written content of a file. + * + * An entry is added by + * + * # echo 'deny_rewrite /var/log/messages' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and is deleted by + * + * # echo 'delete deny_rewrite /var/log/messages' > \ + * /sys/kernel/security/tomoyo/exception_policy + * + * and all entries are retrieved by + * + * # grep ^deny_rewrite /sys/kernel/security/tomoyo/exception_policy + * + * In the example above, if a process requested to rewrite /var/log/messages , + * the process can't rewrite unless the domain which that process belongs to + * has "allow_rewrite /var/log/messages" entry. + * + * It is not a desirable behavior that we have to add "\040(deleted)" suffix + * when we want to allow rewriting already unlink()ed file. As of now, + * LSM version of TOMOYO is using __d_path() for calculating pathname. + * Non LSM version of TOMOYO is using its own function which doesn't append + * " (deleted)" suffix if the file is already unlink()ed; so that we don't + * need to worry whether the file is already unlink()ed or not. + */ static LIST_HEAD(tomoyo_no_rewrite_list); static DECLARE_RWSEM(tomoyo_no_rewrite_list_lock); |