Commit 78271d69 authored by Chuck Lever's avatar Chuck Lever Committed by Li Lingfeng
Browse files

NFSD: Prevent a potential integer overflow 

stable inclusion
from stable-v4.19.325
commit 745f7ce5a95e783ba62fe774325829466aec2aa8
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBDHG9
CVE: CVE-2024-53146

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=745f7ce5a95e783ba62fe774325829466aec2aa8



--------------------------------

commit 7f33b92e5b18e904a481e6e208486da43e4dc841 upstream.

If the tag length is >= U32_MAX - 3 then the "length + 4" addition
can result in an integer overflow. Address this by splitting the
decoding into several steps so that decode_cb_compound4res() does
not have to perform arithmetic on the unsafe length value.

Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
  fs/nfsd/nfs4callback.c
[Commit eb72f484 ("NFS: Remove print_overflow_msg()") remove
print_overflow_msg.]
Signed-off-by: default avatarLi Lingfeng <lilingfeng3@huawei.com>
parent 4dc4cec0

fs/nfsd/nfs4callback.c

+7 −7
Original line number Diff line number Diff line
@@ -294,17 +294,17 @@ static int decode_cb_compound4res(struct xdr_stream *xdr, 
	u32 length;

	__be32 *p;



	p = xdr_inline_decode(xdr, 4 + 4);

	p = xdr_inline_decode(xdr, XDR_UNIT);

	if (unlikely(p == NULL))

		goto out_overflow;

	hdr->status = be32_to_cpup(p++);

	hdr->status = be32_to_cpup(p);

	/* Ignore the tag */

	length = be32_to_cpup(p++);

	p = xdr_inline_decode(xdr, length + 4);

	if (unlikely(p == NULL))

	if (xdr_stream_decode_u32(xdr, &length) < 0)

		goto out_overflow;

	if (xdr_inline_decode(xdr, length) == NULL)

		goto out_overflow;

	if (xdr_stream_decode_u32(xdr, &hdr->nops) < 0)

		goto out_overflow;

	p += XDR_QUADLEN(length);

	hdr->nops = be32_to_cpup(p);

	return 0;

out_overflow:

	print_overflow_msg(__func__, xdr);