bpf: Guard stack limits against 32bit overflow

mainline inclusion
from mainline-v6.8-rc1
commit 1d38a9ee81570c4bd61f557832dead4d6f816760
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9Q9EW
CVE: CVE-2023-52676

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1d38a9ee8157

--------------------------------

This patch promotes the arithmetic around checking stack bounds to be
done in the 64-bit domain, instead of the current 32bit. The arithmetic
implies adding together a 64-bit register with a int offset. The
register was checked to be below 1<<29 when it was variable, but not
when it was fixed. The offset either comes from an instruction (in which
case it is 16 bit), from another register (in which case the caller
checked it to be below 1<<29 [1]), or from the size of an argument to a
kfunc (in which case it can be a u32 [2]). Between the register being
inconsistently checked to be below 1<<29, and the offset being up to an
u32, it appears that we were open to overflowing the `int`s which were
currently used for arithmetic.

[1] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e50f6cd80eb10235fe3e9/kernel/bpf/verifier.c#L7494-L7498
[2] https://github.com/torvalds/linux/blob/815fb87b753055df2d9e50f6cd80eb10235fe3e9/kernel/bpf/verifier.c#L11904



Reported-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231207041150.229139-4-andreimatei1@gmail.com


Conflicts:
	kernel/bpf/verifier.c
[The conflict is because some modifications were merged by the commit
8463d83a ("bpf: Fix accesses to uninit stack slots")]
Signed-off-by: Pu Lehui <pulehui@huawei.com>