CVE-2024-43840

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

bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG

When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls

__bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them

the struct bpf_tramp_image *im pointer as an argument in R0.

The trampoline generation code uses emit_addr_mov_i64() to emit

instructions for moving the bpf_tramp_image address into R0, but

emit_addr_mov_i64() assumes the address to be in the vmalloc() space

and uses only 48 bits. Because bpf_tramp_image is allocated using

kzalloc(), its address can use more than 48-bits, in this case the

trampoline will pass an invalid address to __bpf_tramp_enter/exit()

causing a kernel crash.

Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64()

as it can work with addresses that are greater than 48-bits.