nvmet: fix a memory leak in nvmet_auth_set_key

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nvmet: fix a memory leak in nvmet_auth_set_key When changing dhchap secrets we need to release the old secrets as well. kmemleak complaint: -- unreferenced object 0xffff8c7f44ed8180 (size 64): comm "check", pid 7304, jiffies 4295686133 (age 72034.246s) hex dump (first 32 bytes): 44 48 48 43 2d 31 3a 30 30 3a 4c 64 4c 4f 64 71 DHHC-1:00:LdLOdq 79 56 69 67 77 48 55 32 6d 5a 59 4c 7a 35 59 38 yVigwHU2mZYLz5Y8 backtrace: [<00000000b6fc5071>] kstrdup+0x2e/0x60 [<00000000f0f4633f>] 0xffffffffc0e07ee6 [<0000000053006c05>] 0xffffffffc0dff783 [<00000000419ae922>] configfs_write_iter+0xb1/0x120 [<000000008183c424>] vfs_write+0x2be/0x3c0 [<000000009005a2a5>] ksys_write+0x5f/0xe0 [<00000000cd495c89>] do_syscall_64+0x38/0x90 [<00000000f2a84ac5>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

References

• https://git.kernel.org/stable/c/65710ea51d4a185592c7b14c9e33d0c4a364f074
• https://git.kernel.org/stable/c/0a52566279b4ee65ecd2503d7b7342851f84755c