CVE-2021-47068

Description

In the Linux kernel, the following vulnerability has been resolved: net/nfc: fix use-after-free llcp_sock_bind/connect Commits 8a4cd82d ("nfc: fix refcount leak in llcp_sock_connect()") and c33b1cc62 ("nfc: fix refcount leak in llcp_sock_bind()") fixed a refcount leak bug in bind/connect but introduced a use-after-free if the same local is assigned to 2 different sockets. This can be triggered by the following simple program: int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) ); addr.sa_family = AF_NFC; addr.nfc_protocol = NFC_PROTO_NFC_DEP; bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) close(sock1); close(sock2); Fix this by assigning NULL to llcp_sock->local after calling nfc_llcp_local_put. This addresses CVE-2021-23134.

Product status

References

https://git.kernel.org/stable/c/26157c82ba756767b2bd66d28a71b1bc454447f6

https://git.kernel.org/stable/c/ccddad6dd28530e716448e594c9ca7c76ccd0570

https://git.kernel.org/stable/c/18ae4a192a4496e48a5490b52812645d2413307c

https://git.kernel.org/stable/c/48fba458fe54cc2a980a05c13e6c19b8b2cfb610

https://git.kernel.org/stable/c/e32352070bcac22be6ed8ab635debc280bb65b8c

https://git.kernel.org/stable/c/6b7021ed36dabf29e56842e3408781cd3b82ef6e

https://git.kernel.org/stable/c/374cdde4dcc9c909a60713abdbbf96d5e3e09f91

https://git.kernel.org/stable/c/18175fe17ae043a0b81e5d511f8817825784c299

https://git.kernel.org/stable/c/c61760e6940dd4039a7f5e84a6afc9cdbf4d82b6

cve.org CVE-2021-47068

nvd.nist.gov CVE-2021-47068

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