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kern/loongarch64/dl_helper: Avoid undefined behavior when popping from an empty reloc stack

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The return value of grub_loongarch64_stack_pop() is unsigned, so -1 should
not be used in the first place. Replacing with 0 is enough to avoid the
UB in this edge case.

Technically though, proper error handling is needed throughout the
management of the reloc stack, so no unexpected behavior will happen
even in case of malformed object code input (right now, pushes become
no-ops when the stack is full, and garbage results if the stack does not
contain enough operands for an op). The refactor would touch some more
places so would be best done in a separate series.

Fixes: CID 407777
Fixes: CID 407778

Signed-off-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
WANG Xuerui 2023-05-18 10:52:57 +08:00 committed by Daniel Kiper
parent caf11e803c
commit 1c0df7c142
1 changed files with 1 additions and 1 deletions
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grub-core/kern/loongarch64/dl_helper.c
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@ -46,7 +46,7 @@ static grub_uint64_t
grub_loongarch64_stack_pop (grub_loongarch64_stack_t stack)
{
if (stack->top == -1)
return -1;
return 0;
return stack->data[stack->top--];
}