From 7d3e91a89b7adbc2831334def9e494dd9892f9af Mon Sep 17 00:00:00 2001 From: Sven Wegener Date: Sat, 8 Dec 2012 15:30:18 +0100 Subject: [PATCH] NFSv4: Check for buffer length in __nfs4_get_acl_uncached Commit 1f1ea6c "NFSv4: Fix buffer overflow checking in __nfs4_get_acl_uncached" accidently dropped the checking for too small result buffer length. If someone uses getxattr on "system.nfs4_acl" on an NFSv4 mount supporting ACLs, the ACL has not been cached and the buffer suplied is too short, we still copy the complete ACL, resulting in kernel and user space memory corruption. Signed-off-by: Sven Wegener Cc: stable@kernel.org Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 5eec442..05e5f6f 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3937,8 +3937,13 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu goto out_free; } nfs4_write_cached_acl(inode, pages, res.acl_data_offset, res.acl_len); - if (buf) + if (buf) { + if (res.acl_len > buflen) { + ret = -ERANGE; + goto out_free; + } _copy_from_pages(buf, pages, res.acl_data_offset, res.acl_len); + } out_ok: ret = res.acl_len; out_free: -- 2.7.4