Unverified Commit d9e5d310 authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

fsnotify: optionally pass access range in file permission hooks 



In preparation for pre-content permission events with file access range,
move fsnotify_file_perm() hook out of security_file_permission() and into
the callers.

Callers that have the access range information call the new hook
fsnotify_file_area_perm() with the access range.

Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231212094440.250945-6-amir73il@gmail.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent cb383f06

fs/open.c

+4 −0
Original line number Diff line number Diff line
@@ -304,6 +304,10 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) 
	if (ret)

		return ret;



	ret = fsnotify_file_area_perm(file, MAY_WRITE, &offset, len);

	if (ret)

		return ret;



	if (S_ISFIFO(inode->i_mode))

		return -ESPIPE;

fs/read_write.c

+8 −2
Original line number Diff line number Diff line
@@ -354,6 +354,9 @@ SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, 


int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)

{

	int mask = read_write == READ ? MAY_READ : MAY_WRITE;

	int ret;



	if (unlikely((ssize_t) count < 0))

		return -EINVAL;
@@ -371,8 +374,11 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t 
		}

	}



	return security_file_permission(file,

				read_write == READ ? MAY_READ : MAY_WRITE);

	ret = security_file_permission(file, mask);

	if (ret)

		return ret;



	return fsnotify_file_area_perm(file, mask, ppos, count);

}

EXPORT_SYMBOL(rw_verify_area);

fs/readdir.c

+4 −0
Original line number Diff line number Diff line
@@ -96,6 +96,10 @@ int iterate_dir(struct file *file, struct dir_context *ctx) 
	if (res)

		goto out;



	res = fsnotify_file_perm(file, MAY_READ);

	if (res)

		goto out;



	res = down_read_killable(&inode->i_rwsem);

	if (res)

		goto out;

fs/remap_range.c

+7 −1
Original line number Diff line number Diff line
@@ -102,7 +102,9 @@ static int generic_remap_checks(struct file *file_in, loff_t pos_in, 
static int remap_verify_area(struct file *file, loff_t pos, loff_t len,

			     bool write)

{

	int mask = write ? MAY_WRITE : MAY_READ;

	loff_t tmp;

	int ret;



	if (unlikely(pos < 0 || len < 0))

		return -EINVAL;
@@ -110,7 +112,11 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len, 
	if (unlikely(check_add_overflow(pos, len, &tmp)))

		return -EINVAL;



	return security_file_permission(file, write ? MAY_WRITE : MAY_READ);

	ret = security_file_permission(file, mask);

	if (ret)

		return ret;



	return fsnotify_file_area_perm(file, mask, &pos, len);

}



/*

include/linux/fsnotify.h

+11 −2
Original line number Diff line number Diff line
@@ -101,9 +101,10 @@ static inline int fsnotify_file(struct file *file, __u32 mask) 
}



/*

 * fsnotify_file_perm - permission hook before file access

 * fsnotify_file_area_perm - permission hook before access to file range

 */

static inline int fsnotify_file_perm(struct file *file, int perm_mask)

static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,

					  const loff_t *ppos, size_t count)

{

	__u32 fsnotify_mask = FS_ACCESS_PERM;
@@ -120,6 +121,14 @@ static inline int fsnotify_file_perm(struct file *file, int perm_mask) 
	return fsnotify_file(file, fsnotify_mask);

}



/*

 * fsnotify_file_perm - permission hook before file access

 */

static inline int fsnotify_file_perm(struct file *file, int perm_mask)

{

	return fsnotify_file_area_perm(file, perm_mask, NULL, 0);

}



/*

 * fsnotify_open_perm - permission hook before file open

 */