| Message ID | 20210519004901.3829541-14-viro@zeniv.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/14] d_path: "\0" is {0,0}, not {0} | expand |
> -----Original Message----- > From: Al Viro <viro@ftp.linux.org.uk> On Behalf Of Al Viro > Sent: Wednesday, May 19, 2021 8:49 AM > To: Linus Torvalds <torvalds@linux-foundation.org> > Cc: Justin 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 14/14] getcwd(2): clean up error handling > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> > --- Reviewed-by: Jia He <justin.he@arm.com> -- Cheers, Justin (Jia He)
diff --git a/fs/d_path.c b/fs/d_path.c index 8a9cd44f6689..23a53f7b5c71 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -390,9 +390,11 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) rcu_read_lock(); get_fs_root_and_pwd_rcu(current->fs, &root, &pwd); - error = -ENOENT; - if (!d_unlinked(pwd.dentry)) { - unsigned long len; + if (unlikely(d_unlinked(pwd.dentry))) { + rcu_read_unlock(); + error = -ENOENT; + } else { + unsigned len; DECLARE_BUFFER(b, page, PATH_MAX); prepend(&b, "", 1); @@ -400,23 +402,16 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) prepend(&b, "(unreachable)", 13); rcu_read_unlock(); - if (b.len < 0) { - error = -ENAMETOOLONG; - goto out; - } - - error = -ERANGE; len = PATH_MAX - b.len; - if (len <= size) { + if (unlikely(len > PATH_MAX)) + error = -ENAMETOOLONG; + else if (unlikely(len > size)) + error = -ERANGE; + else if (copy_to_user(buf, b.buf, len)) + error = -EFAULT; + else error = len; - if (copy_to_user(buf, b.buf, len)) - error = -EFAULT; - } - } else { - rcu_read_unlock(); } - -out: __putname(page); return error; }
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- fs/d_path.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)