From 81e9b93aab9217cf7cb508f64b19fc1c0df024b5 Mon Sep 17 00:00:00 2001 From: iximeow Date: Thu, 19 Nov 2020 18:13:24 -0800 Subject: fix decoding of rex-prefixed modrm+sib operands selecting index 0b100 and base 0b101 for memory operands with a base, index, and displacement either the wrong base would be selected (register number ignored, so only `*ax` or `r8*` would be reported), or yaxpeax-x86 would report a base register is present when it is not (`RegIndexBaseScaleDisp` when the operand is actually `RegScaleDisp`) thank you to Evan Johnson for catching and reporting this bug! also bump crate version to 0.1.4 as this will be immediately tagged and released. --- test/long_mode/mod.rs | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'test/long_mode') diff --git a/test/long_mode/mod.rs b/test/long_mode/mod.rs index 3b31dbb..8489822 100644 --- a/test/long_mode/mod.rs +++ b/test/long_mode/mod.rs @@ -109,6 +109,17 @@ fn test_modrm_decode() { test_display(&[0x41, 0x33, 0x84, 0xa5, 0x11, 0x22, 0x33, 0x44], "xor eax, [r13 + 0x44332211]"); test_display(&[0x33, 0x04, 0xe5, 0x11, 0x22, 0x33, 0x44], "xor eax, [0x44332211]"); test_display(&[0x41, 0x33, 0x04, 0xe5, 0x11, 0x22, 0x33, 0x44], "xor eax, [0x44332211]"); + + // specifically sib with base == 0b101 + // mod bits 00 + test_display(&[0x42, 0x33, 0x34, 0x25, 0x20, 0x30, 0x40, 0x50], "xor esi, [r12 * 1 + 0x50403020]"); + test_display(&[0x43, 0x33, 0x34, 0x25, 0x20, 0x30, 0x40, 0x50], "xor esi, [r12 * 1 + 0x50403020]"); + // mod bits 01 + test_display(&[0x42, 0x33, 0x74, 0x25, 0x20], "xor esi, [rbp + r12 * 1 + 0x20]"); + test_display(&[0x43, 0x33, 0x74, 0x25, 0x20], "xor esi, [r13 + r12 * 1 + 0x20]"); + // mod bits 10 + test_display(&[0x42, 0x33, 0xb4, 0x25, 0x20, 0x30, 0x40, 0x50], "xor esi, [rbp + r12 * 1 + 0x50403020]"); + test_display(&[0x43, 0x33, 0xb4, 0x25, 0x20, 0x30, 0x40, 0x50], "xor esi, [r13 + r12 * 1 + 0x50403020]"); } #[test] -- cgit v1.1