CVE-2021-47316 Information

Description

In the Linux kernel the following vulnerability has been resolved:

nfsd: fix NULL dereference in nfs3svc_encode_getaclres

In error cases the dentry may be NULL.

Before 20798dfe249a the encoder also checked dentry and d_really_is_positive(dentry) but that looks like overkill to me–zero status should be enough to guarantee a positive dentry.

This isn’t the first time we’ve seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn’t spot any similar bugs.

Reference

https://git.kernel.org/stable/c/650e6f383a6eb40f7c0a010982a74ab4b6893870 https://git.kernel.org/stable/c/ab1016d39cc052064e32f25ad18ef8767a0ee3b8