From: Chuck Lever chuck.lever@oracle.com

stable inclusion from stable-v5.10.231 commit 3c5f545c9a1f8a1869246f6f3ae8c17289d6a841 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=...

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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: Dan Carpenter dan.carpenter@linaro.org Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Lingfeng lilingfeng3@huawei.com --- fs/nfsd/nfs4callback.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index bd79fc4934f0..9b692bcacd4b 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -286,17 +286,17 @@ 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: return -EIO;