Commit dd937340 authored by Casey Schaufler's avatar Casey Schaufler Committed by Paul Moore
Browse files

Smack: Provide read control for io_uring_cmd 



Limit io_uring "cmd" options to files for which the caller has
Smack read access. There may be cases where the cmd option may
be closer to a write access than a read, but there is no way
to make that determination.

Cc: stable@vger.kernel.org
Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 70752795

security/smack/smack_lsm.c

+32 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#include <linux/fs_context.h>

#include <linux/fs_parser.h>

#include <linux/watch_queue.h>

#include <linux/io_uring.h>

#include "smack.h"



#define TRANS_TRUE	"TRUE"
@@ -4732,6 +4733,36 @@ static int smack_uring_sqpoll(void) 
	return -EPERM;

}



/**

 * smack_uring_cmd - check on file operations for io_uring

 * @ioucmd: the command in question

 *

 * Make a best guess about whether a io_uring "command" should

 * be allowed. Use the same logic used for determining if the

 * file could be opened for read in the absence of better criteria.

 */

static int smack_uring_cmd(struct io_uring_cmd *ioucmd)

{

	struct file *file = ioucmd->file;

	struct smk_audit_info ad;

	struct task_smack *tsp;

	struct inode *inode;

	int rc;



	if (!file)

		return -EINVAL;



	tsp = smack_cred(file->f_cred);

	inode = file_inode(file);



	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);

	smk_ad_setfield_u_fs_path(&ad, file->f_path);

	rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad);

	rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc);



	return rc;

}



#endif /* CONFIG_IO_URING */



struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
@@ -4889,6 +4920,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = { 
#ifdef CONFIG_IO_URING

	LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds),

	LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll),

	LSM_HOOK_INIT(uring_cmd, smack_uring_cmd),

#endif

};