bpf, arm64: Fix address emission with tag-based KASAN enabled

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix address emission with tag-based KASAN enabled When BPF_TRAMP_F_CALL_ORIG is enabled, the address of a bpf_tramp_image struct on the stack is passed during the size calculation pass and an address on the heap is passed during code generation. This may cause a heap buffer overflow if the heap address is tagged because emit_a64_mov_i64() will emit longer code than it did during the size calculation pass. The same problem could occur without tag-based KASAN if one of the 16-bit words of the stack address happened to be all-ones during the size calculation pass. Fix the problem by assuming the worst case (4 instructions) when calculating the size of the bpf_tramp_image address emission.

References

• https://git.kernel.org/stable/c/9e80f366ebfdfafc685fe83a84c34f7ef01cbe88
• https://git.kernel.org/stable/c/f521c2a0c0c4585f36d912bf62c852b88682c4f2
• https://git.kernel.org/stable/c/7db1a2121f3c7903b8e397392beec563c3d00950
• https://git.kernel.org/stable/c/a552e2ef5fd1a6c78267cd4ec5a9b49aa11bbb1c