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injector: push apart overlapping traps #1739

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merged 1 commit into from
Jul 22, 2024
Merged

injector: push apart overlapping traps #1739

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7 changes: 7 additions & 0 deletions src/libinjector/linux/linux_utils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -177,6 +177,8 @@ addr_t find_vdso(drakvuf_t drakvuf, drakvuf_trap_info_t* info)
addr_t find_syscall(drakvuf_t drakvuf, drakvuf_trap_info_t* info, addr_t vdso)
{
vmi_instance_t vmi = drakvuf_lock_and_get_vmi(drakvuf);
// skip the syscall we are currently on
addr_t skip_addr = info->regs->rip - 2;

ACCESS_CONTEXT(ctx,
.translate_mechanism = VMI_TM_PROCESS_PID,
Expand All @@ -202,6 +204,11 @@ addr_t find_syscall(drakvuf_t drakvuf, drakvuf_trap_info_t* info, addr_t vdso)

char syscall[] = { 0xf, 0x5 };
void* syscall_substring_address = memmem(vdso_memory, size, (void*)syscall, 2);
if (syscall_substring_address && (vdso + (syscall_substring_address - vdso_memory)) == skip_addr)
{
PRINT_DEBUG("Skip syscall offset, as it overlaps with current trap\n");
syscall_substring_address = memmem(syscall_substring_address + 1, size, (void*)syscall, 2);
}
int syscall_offset = 0;
if (!syscall_substring_address)
{
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