de8cd83e91
The fanotify interface allows user space daemons to make access control decisions. Under common criteria requirements, we need to optionally record decisions based on policy. This patch adds a bit mask, FAN_AUDIT, that a user space daemon can 'or' into the response decision which will tell the kernel that it made a decision and record it. It would be used something like this in user space code: response.response = FAN_DENY | FAN_AUDIT; write(fd, &response, sizeof(struct fanotify_response)); When the syscall ends, the audit system will record the decision as a AUDIT_FANOTIFY auxiliary record to denote that the reason this event occurred is the result of an access control decision from fanotify rather than DAC or MAC policy. A sample event looks like this: type=PATH msg=audit(1504310584.332:290): item=0 name="./evil-ls" inode=1319561 dev=fc:03 mode=0100755 ouid=1000 ogid=1000 rdev=00:00 obj=unconfined_u:object_r:user_home_t:s0 nametype=NORMAL type=CWD msg=audit(1504310584.332:290): cwd="/home/sgrubb" type=SYSCALL msg=audit(1504310584.332:290): arch=c000003e syscall=2 success=no exit=-1 a0=32cb3fca90 a1=0 a2=43 a3=8 items=1 ppid=901 pid=959 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="bash" exe="/usr/bin/bash" subj=unconfined_u:unconfined_r:unconfined_t: s0-s0:c0.c1023 key=(null) type=FANOTIFY msg=audit(1504310584.332:290): resp=2 Prior to using the audit flag, the developer needs to call fanotify_init or'ing in FAN_ENABLE_AUDIT to ensure that the kernel supports auditing. The calling process must also have the CAP_AUDIT_WRITE capability. Signed-off-by: sgrubb <sgrubb@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
#ifndef _UAPI_LINUX_FANOTIFY_H
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#define _UAPI_LINUX_FANOTIFY_H
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#include <linux/types.h>
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/* the following events that user-space can register for */
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#define FAN_ACCESS 0x00000001 /* File was accessed */
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#define FAN_MODIFY 0x00000002 /* File was modified */
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#define FAN_CLOSE_WRITE 0x00000008 /* Writtable file closed */
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#define FAN_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
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#define FAN_OPEN 0x00000020 /* File was opened */
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#define FAN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
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#define FAN_OPEN_PERM 0x00010000 /* File open in perm check */
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#define FAN_ACCESS_PERM 0x00020000 /* File accessed in perm check */
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#define FAN_ONDIR 0x40000000 /* event occurred against dir */
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#define FAN_EVENT_ON_CHILD 0x08000000 /* interested in child events */
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/* helper events */
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#define FAN_CLOSE (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
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/* flags used for fanotify_init() */
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#define FAN_CLOEXEC 0x00000001
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#define FAN_NONBLOCK 0x00000002
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/* These are NOT bitwise flags. Both bits are used togther. */
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#define FAN_CLASS_NOTIF 0x00000000
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#define FAN_CLASS_CONTENT 0x00000004
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#define FAN_CLASS_PRE_CONTENT 0x00000008
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#define FAN_ALL_CLASS_BITS (FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
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FAN_CLASS_PRE_CONTENT)
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#define FAN_UNLIMITED_QUEUE 0x00000010
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#define FAN_UNLIMITED_MARKS 0x00000020
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#define FAN_ENABLE_AUDIT 0x00000040
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#define FAN_ALL_INIT_FLAGS (FAN_CLOEXEC | FAN_NONBLOCK | \
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FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\
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FAN_UNLIMITED_MARKS)
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/* flags used for fanotify_modify_mark() */
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#define FAN_MARK_ADD 0x00000001
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#define FAN_MARK_REMOVE 0x00000002
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#define FAN_MARK_DONT_FOLLOW 0x00000004
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#define FAN_MARK_ONLYDIR 0x00000008
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#define FAN_MARK_MOUNT 0x00000010
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#define FAN_MARK_IGNORED_MASK 0x00000020
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#define FAN_MARK_IGNORED_SURV_MODIFY 0x00000040
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#define FAN_MARK_FLUSH 0x00000080
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#define FAN_ALL_MARK_FLAGS (FAN_MARK_ADD |\
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FAN_MARK_REMOVE |\
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FAN_MARK_DONT_FOLLOW |\
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FAN_MARK_ONLYDIR |\
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FAN_MARK_MOUNT |\
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FAN_MARK_IGNORED_MASK |\
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FAN_MARK_IGNORED_SURV_MODIFY |\
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FAN_MARK_FLUSH)
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/*
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* All of the events - we build the list by hand so that we can add flags in
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* the future and not break backward compatibility. Apps will get only the
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* events that they originally wanted. Be sure to add new events here!
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*/
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#define FAN_ALL_EVENTS (FAN_ACCESS |\
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FAN_MODIFY |\
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FAN_CLOSE |\
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FAN_OPEN)
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/*
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* All events which require a permission response from userspace
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*/
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#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
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FAN_ACCESS_PERM)
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#define FAN_ALL_OUTGOING_EVENTS (FAN_ALL_EVENTS |\
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FAN_ALL_PERM_EVENTS |\
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FAN_Q_OVERFLOW)
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#define FANOTIFY_METADATA_VERSION 3
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struct fanotify_event_metadata {
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__u32 event_len;
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__u8 vers;
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__u8 reserved;
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__u16 metadata_len;
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__aligned_u64 mask;
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__s32 fd;
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__s32 pid;
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};
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struct fanotify_response {
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__s32 fd;
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__u32 response;
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};
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/* Legit userspace responses to a _PERM event */
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#define FAN_ALLOW 0x01
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#define FAN_DENY 0x02
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#define FAN_AUDIT 0x10 /* Bit mask to create audit record for result */
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/* No fd set in event */
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#define FAN_NOFD -1
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/* Helper functions to deal with fanotify_event_metadata buffers */
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#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
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#define FAN_EVENT_NEXT(meta, len) ((len) -= (meta)->event_len, \
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(struct fanotify_event_metadata*)(((char *)(meta)) + \
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(meta)->event_len))
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#define FAN_EVENT_OK(meta, len) ((long)(len) >= (long)FAN_EVENT_METADATA_LEN && \
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(long)(meta)->event_len >= (long)FAN_EVENT_METADATA_LEN && \
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(long)(meta)->event_len <= (long)(len))
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#endif /* _UAPI_LINUX_FANOTIFY_H */
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