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closure_bridge_template LR 寄存器保存错误 #245

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ByteSecurity opened this issue Nov 11, 2023 · 0 comments
Open

closure_bridge_template LR 寄存器保存错误 #245

ByteSecurity opened this issue Nov 11, 2023 · 0 comments

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@ByteSecurity
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ByteSecurity commented Nov 11, 2023 •
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环境：

XR, ios 14.7, arm64

问题

在arm64 closure_bridge_template 实现中， 直接使用 xASM("stp x29, x30, [sp, #(28*8)]"); 来保存LR 寄存器， 对于 common_closure_bridge_handler 来说应该是错误的。

因为这段函数是通过 两次 BLR X17 跳转的， 他保存的是他的上一层跳转函数的， 而不是原始函数的 LR

在 common_closure_bridge_handler 中使用 ctx->lr 也不是 closure_bridge_template 保存的 X30， 是取的 ctx+0x108的位置（x0 是ctx+0x18 是对的），结果很奇怪
@ByteSecurity ByteSecurity changed the title 跳转过程中 LR 寄存器保存错误 closure_bridge_template LR 寄存器保存错误 Nov 11, 2023
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