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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2019-03-30 10:21:07 +0900
committerTrond Myklebust <trond.myklebust@hammerspace.com>2019-04-11 15:23:48 -0400
commit7c2bd9a39845bfb6d72ddb55ce737650271f6f96 (patch)
tree1418f0b2012665a16921443a17856c53ee3eb18b /fs/nfs
parent582549e3fbe137eb6ce9be591aca25c2222a36b4 (diff)
downloadlinux-7c2bd9a39845bfb6d72ddb55ce737650271f6f96.tar.gz
NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.
syzbot is reporting uninitialized value at rpc_sockaddr2uaddr() [1]. This
is because syzbot is setting AF_INET6 to "struct sockaddr_in"->sin_family
(which is embedded into user-visible "struct nfs_mount_data" structure)
despite nfs23_validate_mount_data() cannot pass sizeof(struct sockaddr_in6)
bytes of AF_INET6 address to rpc_sockaddr2uaddr().

Since "struct nfs_mount_data" structure is user-visible, we can't change
"struct nfs_mount_data" to use "struct sockaddr_storage". Therefore,
assuming that everybody is using AF_INET family when passing address via
"struct nfs_mount_data"->addr, reject if its sin_family is not AF_INET.

[1] https://syzkaller.appspot.com/bug?id=599993614e7cbbf66bc2656a919ab2a95fb5d75c

Reported-by: syzbot <syzbot+047a11c361b872896a4f@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/super.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 23790c7b2289..c27ac96a95bd 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2041,7 +2041,8 @@ static int nfs23_validate_mount_data(void *options,
 		memcpy(sap, &data->addr, sizeof(data->addr));
 		args->nfs_server.addrlen = sizeof(data->addr);
 		args->nfs_server.port = ntohs(data->addr.sin_port);
-		if (!nfs_verify_server_address(sap))
+		if (sap->sa_family != AF_INET ||
+		    !nfs_verify_server_address(sap))
 			goto out_no_address;
 
 		if (!(data->flags & NFS_MOUNT_TCP))