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authorH.J. Lu <hjl.tools@gmail.com>2024-01-06 14:03:37 -0800
committerH.J. Lu <hjl.tools@gmail.com>2024-01-06 14:25:49 -0800
commit0f9afc265a4a0f4ba658d7f71c9602a3fda3538e (patch)
tree1415b8a9d056e30603381edf9728ebb4a3b9f063 /soft-fp/fixhfdi.c
parentb96a2eba2fcca37deea221a18c998ee0084a5d21 (diff)
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x32: Handle displacement overflow in PLT rewrite [BZ #31218]
PLT rewrite calculated displacement with

ElfW(Addr) disp = value - branch_start - JMP32_INSN_SIZE;

On x32, displacement from 0xf7fbe060 to 0x401030 was calculated as

unsigned int disp = 0x401030 - 0xf7fbe060 - 5;

with disp == 0x8442fcb and caused displacement overflow. The PLT entry
was changed to:

0xf7fbe060 <+0>:	e9 cb 2f 44 08     	jmp    0x401030
0xf7fbe065 <+5>:	cc                 	int3
0xf7fbe066 <+6>:	cc                 	int3
0xf7fbe067 <+7>:	cc                 	int3
0xf7fbe068 <+8>:	cc                 	int3
0xf7fbe069 <+9>:	cc                 	int3
0xf7fbe06a <+10>:	cc                 	int3
0xf7fbe06b <+11>:	cc                 	int3
0xf7fbe06c <+12>:	cc                 	int3
0xf7fbe06d <+13>:	cc                 	int3
0xf7fbe06e <+14>:	cc                 	int3
0xf7fbe06f <+15>:	cc                 	int3

x32 has 32-bit address range, but it doesn't wrap address around at 4GB,
JMP target was changed to 0x100401030 (0xf7fbe060LL + 0x8442fcbLL + 5),
which is above 4GB.

Always use uint64_t to calculate displacement.  This fixes BZ #31218.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Diffstat (limited to 'soft-fp/fixhfdi.c')
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