CVE-2021-47312

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: Fix dereference of null pointer flow

In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then nft_flow_rule_create is not called and flow is NULL. The subsequent error handling execution via label err_destroy_flow_rule will lead to a null pointer dereference on flow when calling nft_flow_rule_destroy. Since the error path to err_destroy_flow_rule has to cater for null and non-null flows, only call nft_flow_rule_destroy if flow is non-null to fix this issue.

Addresses-Coverity: (Explicity null dereference)

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/4ca041f919f13783b0b03894783deee00dbca19a
• https://git.kernel.org/stable/c/70a5a1950cca02c5cd161bb3846b4d983eed97d3