From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jia He <justin.he@arm.com>, Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Jonathan Corbet <corbet@lwn.net>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ira Weiny <ira.weiny@intel.com>,
Eric Biggers <ebiggers@google.com>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: [PATCH 05/14] getcwd(2): saner logics around prepend_path() call
Date: Wed, 19 May 2021 00:48:52 +0000 [thread overview]
Message-ID: <20210519004901.3829541-5-viro@zeniv.linux.org.uk> (raw)
In-Reply-To: <20210519004901.3829541-1-viro@zeniv.linux.org.uk>
The only negative value that might get returned by prepend_path() is
-ENAMETOOLONG, and that happens only on overflow. The same goes for
prepend_unreachable(). Overflow is detectable by observing negative
buflen, so we can simplify the control flow around the prepend_path()
call. Expand prepend_unreachable(), while we are at it - that's the
only caller.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/d_path.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/fs/d_path.c b/fs/d_path.c
index 7f3fac544bbb..311d43287572 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -211,11 +211,6 @@ char *d_absolute_path(const struct path *path,
return res;
}
-static int prepend_unreachable(char **buffer, int *buflen)
-{
- return prepend(buffer, buflen, "(unreachable)", 13);
-}
-
static void get_fs_root_rcu(struct fs_struct *fs, struct path *root)
{
unsigned seq;
@@ -414,17 +409,13 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
int buflen = PATH_MAX;
prepend(&cwd, &buflen, "", 1);
- error = prepend_path(&pwd, &root, &cwd, &buflen);
+ if (prepend_path(&pwd, &root, &cwd, &buflen) > 0)
+ prepend(&cwd, &buflen, "(unreachable)", 13);
rcu_read_unlock();
- if (error < 0)
+ if (buflen < 0) {
+ error = -ENAMETOOLONG;
goto out;
-
- /* Unreachable from current root */
- if (error > 0) {
- error = prepend_unreachable(&cwd, &buflen);
- if (error)
- goto out;
}
error = -ERANGE;
--
2.11.0
next prev parent reply other threads:[~2021-05-19 0:51 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 12:25 [PATCH RFC 0/3] make '%pD' print full path for file Jia He
2021-05-08 12:25 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Jia He
2021-05-08 15:30 ` Linus Torvalds
2021-05-08 19:13 ` Al Viro
2021-05-08 20:39 ` Linus Torvalds
2021-05-08 21:05 ` Al Viro
2021-05-08 22:17 ` Linus Torvalds
2021-05-08 22:46 ` Al Viro
2021-05-08 22:48 ` Linus Torvalds
2021-05-08 23:15 ` Al Viro
2021-05-08 23:18 ` Al Viro
2021-05-09 22:58 ` Eric W. Biederman
2021-05-10 12:51 ` Christian Brauner
2021-05-10 7:20 ` Christian Brauner
2021-05-08 22:42 ` Linus Torvalds
2021-05-08 22:47 ` Linus Torvalds
2021-05-09 2:28 ` Al Viro
2021-05-09 2:53 ` Linus Torvalds
2021-05-19 0:43 ` [PATCHSET] d_path cleanups Al Viro
2021-05-19 0:48 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Al Viro
2021-05-19 0:48 ` [PATCH 02/14] d_path: saner calling conventions for __dentry_path() Al Viro
2021-06-25 9:32 ` Justin He
2021-07-07 4:52 ` Justin He
2021-05-19 0:48 ` [PATCH 03/14] d_path: regularize handling of root dentry in __dentry_path() Al Viro
2021-07-07 4:50 ` Justin He
2021-05-19 0:48 ` [PATCH 04/14] d_path: get rid of path_with_deleted() Al Viro
2021-05-19 0:48 ` Al Viro [this message]
2021-07-07 7:41 ` [PATCH 05/14] getcwd(2): saner logics around prepend_path() call Justin He
2021-05-19 0:48 ` [PATCH 06/14] d_path: don't bother with return value of prepend() Al Viro
2021-06-24 6:13 ` Justin He
2021-05-19 0:48 ` [PATCH 07/14] d_path: lift -ENAMETOOLONG handling into callers of prepend_path() Al Viro
2021-06-25 9:18 ` Justin He
2021-06-28 5:20 ` Justin He
2021-05-19 0:48 ` [PATCH 08/14] d_path: make prepend_name() boolean Al Viro
2021-05-20 9:12 ` Justin He
2021-05-20 9:19 ` Andy Shevchenko
2021-05-20 14:53 ` Petr Mladek
2021-05-20 19:35 ` Al Viro
2021-07-07 7:43 ` Justin He
2021-05-19 0:48 ` [PATCH 09/14] d_path: introduce struct prepend_buffer Al Viro
2021-06-23 13:28 ` Justin He
2021-06-24 9:29 ` Enrico Weigelt, metux IT consult
2021-06-25 0:43 ` Justin He
2021-06-28 16:42 ` Enrico Weigelt, metux IT consult
2021-06-28 17:10 ` Andy Shevchenko
2021-05-19 0:48 ` [PATCH 10/14] d_path: prepend_path(): get rid of vfsmnt Al Viro
2021-05-19 0:48 ` [PATCH 11/14] d_path: prepend_path(): lift resetting b in case when we'd return 3 out of loop Al Viro
2021-05-19 0:48 ` [PATCH 12/14] d_path: prepend_path(): lift the inner loop into a new helper Al Viro
2021-05-19 8:07 ` Andy Shevchenko
2021-05-19 15:55 ` Al Viro
2021-07-07 7:52 ` Justin He
2021-05-19 0:49 ` [PATCH 13/14] d_path: prepend_path() is unlikely to return non-zero Al Viro
2021-06-25 8:00 ` Justin He
2021-06-25 17:58 ` Al Viro
2021-06-28 3:28 ` Justin He
2021-06-28 4:14 ` Al Viro
2021-06-28 4:36 ` Justin He
2021-06-28 4:37 ` Justin He
2021-05-19 0:49 ` [PATCH 14/14] getcwd(2): clean up error handling Al Viro
2021-07-07 8:03 ` Justin He
2021-06-24 6:05 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Justin He
2021-05-19 2:39 ` [PATCHSET] d_path cleanups Linus Torvalds
2021-06-22 14:00 ` Justin He
2021-05-09 2:20 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Al Viro
2021-05-09 4:58 ` Al Viro
2021-05-10 16:16 ` Eric W. Biederman
2021-05-10 15:07 ` Justin He
2021-05-10 17:03 ` Linus Torvalds
2021-05-08 12:25 ` [PATCH RFC 2/3] lib/vsprintf.c: make %pD print full path for file Jia He
2021-05-10 3:46 ` Sergey Senozhatsky
2021-05-10 13:04 ` Petr Mladek
2021-05-10 14:25 ` Justin He
2021-05-27 7:20 ` Justin He
2021-05-27 9:14 ` Petr Mladek
2021-05-08 12:25 ` [PATCH RFC 3/3] s390/hmcdrv: remove the redundant directory path in debug message Jia He
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