| From | Greg Kroah-Hartman <> | Subject | [ 041/123] NFSv4: Check for buffer length in __nfs4_get_acl_uncached | Date | Wed, 9 Jan 2013 12:34:40 -0800 |
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3.7-stable review patch. If anyone has any objections, please let me know.
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From: Sven Wegener <sven.wegener@stealer.net>
commit 7d3e91a89b7adbc2831334def9e494dd9892f9af upstream.
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 <sven.wegener@stealer.net> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nfs/nfs4proc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3937,8 +3937,13 @@ static ssize_t __nfs4_get_acl_uncached(s 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:
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