linux-kernel - [PATCH v2 04/15] vfs: fix readlinkat to retry on ESTALE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 22 May 2012 10:12:08 -0400
From:	Jeff Layton <jlayton@...hat.com>
To:	viro@...IV.linux.org.uk
Cc:	inux-fsdevel@...r.kernel.org, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, miklos@...redi.hu, hch@...radead.org,
	michael.brantley@...haw.com, pstaubach@...grid.com
Subject: [PATCH v2 04/15] vfs: fix readlinkat to retry on ESTALE

Signed-off-by: Jeff Layton <jlayton@...hat.com>
---
 fs/stat.c |   21 +++++++++++++++++----
 1 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 60a8813..671106d 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -307,14 +307,25 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 	struct path path;
 	int error;
 	int empty = 0;
+	char *name;
+	unsigned int try = 0;
+	unsigned int lookup_flags = LOOKUP_EMPTY;
 
 	if (bufsiz <= 0)
 		return -EINVAL;
 
-	error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
-	if (!error) {
-		struct inode *inode = path.dentry->d_inode;
+	name = getname_flags(pathname, lookup_flags, &empty);
+	if (IS_ERR(name))
+		return PTR_ERR(name);
+
+	do {
+		struct inode *inode;
+
+		error = kern_path_at(dfd, name, lookup_flags, &path);
+		if (error)
+			break;
 
+		inode = path.dentry->d_inode;
 		error = empty ? -ENOENT : -EINVAL;
 		if (inode->i_op->readlink) {
 			error = security_inode_readlink(path.dentry);
@@ -325,7 +336,9 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 			}
 		}
 		path_put(&path);
-	}
+		lookup_flags |= LOOKUP_REVAL;
+	} while (retry_estale(error, try++));
+	putname(name);
 	return error;
 }
 
-- 
1.7.7.6

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/