Commit 245d7369 authored by Kees Cook's avatar Kees Cook Committed by Paul Moore
Browse files

audit: Report suspicious O_CREAT usage 



This renames the very specific audit_log_link_denied() to
audit_log_path_denied() and adds the AUDIT_* type as an argument. This
allows for the creation of the new AUDIT_ANOM_CREAT that can be used to
report the fifo/regular file creation restrictions that were introduced
in commit 30aba665 ("namei: allow restricted O_CREAT of FIFOs and
regular files").

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 54ecb8f7

fs/namei.c

+6 −2
Original line number Diff line number Diff line
@@ -925,7 +925,7 @@ static inline int may_follow_link(struct nameidata *nd) 
		return -ECHILD;



	audit_inode(nd->name, nd->stack[0].link.dentry, 0);

	audit_log_link_denied("follow_link");

	audit_log_path_denied(AUDIT_ANOM_LINK, "follow_link");

	return -EACCES;

}
@@ -993,7 +993,7 @@ static int may_linkat(struct path *link) 
	if (safe_hardlink_source(inode) || inode_owner_or_capable(inode))

		return 0;



	audit_log_link_denied("linkat");

	audit_log_path_denied(AUDIT_ANOM_LINK, "linkat");

	return -EPERM;

}
@@ -1031,6 +1031,10 @@ static int may_create_in_sticky(struct dentry * const dir, 
	    (dir->d_inode->i_mode & 0020 &&

	     ((sysctl_protected_fifos >= 2 && S_ISFIFO(inode->i_mode)) ||

	      (sysctl_protected_regular >= 2 && S_ISREG(inode->i_mode))))) {

		const char *operation = S_ISFIFO(inode->i_mode) ?

					"sticky_create_fifo" :

					"sticky_create_regular";

		audit_log_path_denied(AUDIT_ANOM_CREAT, operation);

		return -EACCES;

	}

	return 0;

include/linux/audit.h

+3 −2
Original line number Diff line number Diff line
@@ -156,7 +156,8 @@ extern void audit_log_d_path(struct audit_buffer *ab, 
					     const struct path *path);

extern void		    audit_log_key(struct audit_buffer *ab,

					  char *key);

extern void		    audit_log_link_denied(const char *operation);

extern void		    audit_log_path_denied(int type,

						  const char *operation);

extern void		    audit_log_lost(const char *message);



extern int audit_log_task_context(struct audit_buffer *ab);
@@ -217,7 +218,7 @@ static inline void audit_log_d_path(struct audit_buffer *ab, 
{ }

static inline void audit_log_key(struct audit_buffer *ab, char *key)

{ }

static inline void audit_log_link_denied(const char *string)

static inline void audit_log_path_denied(int type, const char *operation)

{ }

static inline int audit_log_task_context(struct audit_buffer *ab)

{

include/uapi/linux/audit.h

+1 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ 
#define AUDIT_ANOM_PROMISCUOUS      1700 /* Device changed promiscuous mode */

#define AUDIT_ANOM_ABEND            1701 /* Process ended abnormally */

#define AUDIT_ANOM_LINK		    1702 /* Suspicious use of file links */

#define AUDIT_ANOM_CREAT	    1703 /* Suspicious file creation */

#define AUDIT_INTEGRITY_DATA	    1800 /* Data integrity verification */

#define AUDIT_INTEGRITY_METADATA    1801 /* Metadata integrity verification */

#define AUDIT_INTEGRITY_STATUS	    1802 /* Integrity enable status */

kernel/audit.c

+6 −5
Original line number Diff line number Diff line
@@ -2155,18 +2155,19 @@ void audit_log_task_info(struct audit_buffer *ab) 
EXPORT_SYMBOL(audit_log_task_info);



/**

 * audit_log_link_denied - report a link restriction denial

 * @operation: specific link operation

 * audit_log_path_denied - report a path restriction denial

 * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)

 * @operation: specific operation name

 */

void audit_log_link_denied(const char *operation)

void audit_log_path_denied(int type, const char *operation)

{

	struct audit_buffer *ab;



	if (!audit_enabled || audit_dummy_context())

		return;



	/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */

	ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK);

	/* Generate log with subject, operation, outcome. */

	ab = audit_log_start(audit_context(), GFP_KERNEL, type);

	if (!ab)

		return;

	audit_log_format(ab, "op=%s", operation);