vfs: split out access_override_creds() (94704515) · Commits · 戴 / test

fs/open.c

+24 −10

Original line number	Diff line number	Diff line
		@@ -345,21 +345,14 @@ SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
		* We do this by temporarily clearing all FS-related capabilities and
		* switching the fsuid/fsgid around to the real ones.
		*/
		long do_faccessat(int dfd, const char __user *filename, int mode)
		static const struct cred *access_override_creds(void)
		{
		const struct cred *old_cred;
		struct cred *override_cred;
		struct path path;
		struct inode *inode;
		int res;
		unsigned int lookup_flags = LOOKUP_FOLLOW;

		if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
		return -EINVAL;

		override_cred = prepare_creds();
		if (!override_cred)
		return -ENOMEM;
		return NULL;

		override_cred->fsuid = override_cred->uid;
		override_cred->fsgid = override_cred->gid;
		@@ -394,6 +387,28 @@ long do_faccessat(int dfd, const char __user *filename, int mode)
		override_cred->non_rcu = 1;

		old_cred = override_creds(override_cred);

		/* override_cred() gets its own ref */
		put_cred(override_cred);

		return old_cred;
		}

		long do_faccessat(int dfd, const char __user *filename, int mode)
		{
		struct path path;
		struct inode *inode;
		int res;
		unsigned int lookup_flags = LOOKUP_FOLLOW;
		const struct cred *old_cred;

		if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
		return -EINVAL;

		old_cred = access_override_creds();
		if (!old_cred)
		return -ENOMEM;

		retry:
		res = user_path_at(dfd, filename, lookup_flags, &path);
		if (res)
		@@ -436,7 +451,6 @@ out_path_release:
		}
		out:
		revert_creds(old_cred);
		put_cred(override_cred);
		return res;
		}