Don't Forget To Dereference Table Pointer

darlinghq · Feb 4, 2024 · d370896 · d370896
1 parent a1e0995
commit d370896
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/darling/src/libsystem_kernel/emulation/linux/mach/darling_mach_syscall.S b/darling/src/libsystem_kernel/emulation/linux/mach/darling_mach_syscall.S
@@ -145,8 +145,9 @@ Lentry_hook:
 
 	// void* x10 = __mach_syscall_table[0-x16]
 	neg		x10, x16		// Convert negative syscall number to positive 
-	lsl		x10, x10, #3	// x10 = x9 * 8 (size of a pointer)
-	add		x10, x9, x10
+	lsl		x10, x10, #3	// x10 = syscall_number * 8 (size of a pointer)
+	add		x10, x9, x10	// x10 = __mach_syscall_table + x10
+	ldr		x10, [x10]		// x10 = *x10
 
 	// x10(...)
 	blr		x10

diff --git a/darling/src/libsystem_kernel/emulation/linux/syscalls-table.S b/darling/src/libsystem_kernel/emulation/linux/syscalls-table.S
@@ -188,8 +188,9 @@ Lentry_hook:
 
 	// void* x10 = __bsd_syscall_table[x16]
 	mov		x10, x16
-	lsl		x10, x10, #3 // x10 = x9 * 8 (size of a pointer)
-	add		x10, x9, x10
+	lsl		x10, x10, #3	// x10 = syscall_number * 8 (size of a pointer)
+	add		x10, x9, x10	// x10 = __bsd_syscall_table + x10
+	ldr		x10, [x10]		// x10 = *x10
 
 	// x10(...)
 	blr		x10