diff options
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 17 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.h | 5 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 29 | ||||
| -rw-r--r-- | include/linux/fanotify.h | 4 | ||||
| -rw-r--r-- | include/uapi/linux/fanotify.h | 7 |
5 files changed, 55 insertions, 7 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index da6c3c1c7edf..95646f7c46ca 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -223,7 +223,7 @@ static int fanotify_get_response(struct fsnotify_group *group, struct fanotify_perm_event *event, struct fsnotify_iter_info *iter_info) { - int ret; + int ret, errno; pr_debug("%s: group=%p event=%p\n", __func__, group, event); @@ -262,14 +262,23 @@ static int fanotify_get_response(struct fsnotify_group *group, ret = 0; break; case FAN_DENY: + /* Check custom errno from pre-content events */ + errno = fanotify_get_response_errno(event->response); + if (errno) { + ret = -errno; + break; + } + fallthrough; default: ret = -EPERM; } /* Check if the response should be audited */ - if (event->response & FAN_AUDIT) - audit_fanotify(event->response & ~FAN_AUDIT, - &event->audit_rule); + if (event->response & FAN_AUDIT) { + u32 response = event->response & + (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS); + audit_fanotify(response & ~FAN_AUDIT, &event->audit_rule); + } pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, group, event, ret); diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index 7f06355afa1f..c12cbc270539 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -528,3 +528,8 @@ static inline unsigned int fanotify_mark_user_flags(struct fsnotify_mark *mark) return mflags; } + +static inline u32 fanotify_get_response_errno(int res) +{ + return (res >> FAN_ERRNO_SHIFT) & FAN_ERRNO_MASK; +} diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 6ef3cc7de5e4..19435cd2c41f 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -327,11 +327,12 @@ static int process_access_response(struct fsnotify_group *group, struct fanotify_perm_event *event; int fd = response_struct->fd; u32 response = response_struct->response; + int errno = fanotify_get_response_errno(response); int ret = info_len; struct fanotify_response_info_audit_rule friar; - pr_debug("%s: group=%p fd=%d response=%u buf=%p size=%zu\n", __func__, - group, fd, response, info, info_len); + pr_debug("%s: group=%p fd=%d response=%x errno=%d buf=%p size=%zu\n", + __func__, group, fd, response, errno, info, info_len); /* * make sure the response is valid, if invalid we do nothing and either * userspace can send a valid response or we will clean it up after the @@ -342,7 +343,31 @@ static int process_access_response(struct fsnotify_group *group, switch (response & FANOTIFY_RESPONSE_ACCESS) { case FAN_ALLOW: + if (errno) + return -EINVAL; + break; case FAN_DENY: + /* Custom errno is supported only for pre-content groups */ + if (errno && group->priority != FSNOTIFY_PRIO_PRE_CONTENT) + return -EINVAL; + + /* + * Limit errno to values expected on open(2)/read(2)/write(2) + * of regular files. + */ + switch (errno) { + case 0: + case EIO: + case EPERM: + case EBUSY: + case ETXTBSY: + case EAGAIN: + case ENOSPC: + case EDQUOT: + break; + default: + return -EINVAL; + } break; default: return -EINVAL; diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index c747af064d2c..78f660ebc318 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -132,7 +132,9 @@ /* These masks check for invalid bits in permission responses. */ #define FANOTIFY_RESPONSE_ACCESS (FAN_ALLOW | FAN_DENY) #define FANOTIFY_RESPONSE_FLAGS (FAN_AUDIT | FAN_INFO) -#define FANOTIFY_RESPONSE_VALID_MASK (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS) +#define FANOTIFY_RESPONSE_VALID_MASK \ + (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS | \ + (FAN_ERRNO_MASK << FAN_ERRNO_SHIFT)) /* Do not use these old uapi constants internally */ #undef FAN_ALL_CLASS_BITS diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h index 0636a9c85dd0..bd8167979707 100644 --- a/include/uapi/linux/fanotify.h +++ b/include/uapi/linux/fanotify.h @@ -235,6 +235,13 @@ struct fanotify_response_info_audit_rule { /* Legit userspace responses to a _PERM event */ #define FAN_ALLOW 0x01 #define FAN_DENY 0x02 +/* errno other than EPERM can specified in upper byte of deny response */ +#define FAN_ERRNO_BITS 8 +#define FAN_ERRNO_SHIFT (32 - FAN_ERRNO_BITS) +#define FAN_ERRNO_MASK ((1 << FAN_ERRNO_BITS) - 1) +#define FAN_DENY_ERRNO(err) \ + (FAN_DENY | ((((__u32)(err)) & FAN_ERRNO_MASK) << FAN_ERRNO_SHIFT)) + #define FAN_AUDIT 0x10 /* Bitmask to create audit record for result */ #define FAN_INFO 0x20 /* Bitmask to indicate additional information */ |