CVE-2021-47198

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

scsi: lpfc: Fix use-after-free in lpfc_unreg_rpi() routine

An error is detected with the following report when unloading the driver: KASAN: use-after-free in lpfc_unreg_rpi+0x1b1b

The NLP_REG_LOGIN_SEND nlp_flag is set in lpfc_reg_fab_ctrl_node(), but the flag is not cleared upon completion of the login.

This allows a second call to lpfc_unreg_rpi() to proceed with nlp_rpi set to LPFC_RPI_ALLOW_ERROR. This results in a use after free access when used as an rpi_ids array index.

Fix by clearing the NLP_REG_LOGIN_SEND nlp_flag in lpfc_mbx_cmpl_fc_reg_login().

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/79b20beccea3a3938a8500acef4e6b9d7c66142f
• https://git.kernel.org/stable/c/dbebf865b3239595c1d4dba063b122862583b52a
• https://git.kernel.org/stable/c/79b20beccea3a3938a8500acef4e6b9d7c66142f
• https://git.kernel.org/stable/c/dbebf865b3239595c1d4dba063b122862583b52a