sigreturn: Test more cases

1 files changed, 44 insertions, 10 deletions

diff --git a/sigreturn.c b/sigreturn.c
index 4c2d0f6..3bdd6fd 100644
--- a/sigreturn.c
+++ b/sigreturn.c
@@ -88,11 +88,37 @@ static void setup_ldt(void)
 		.seg_not_present = 0,
 		.useable         = 0
 	};
+	const struct user_desc npcode16_desc = {
+		.entry_number    = 3,
+		.base_addr       = (unsigned long)int3,
+		.limit           = 4095,
+		.seg_32bit       = 1,
+		.contents        = 2, /* Code, not conforming */
+		.read_exec_only  = 0,
+		.limit_in_pages  = 0,
+		.seg_not_present = 1,
+		.useable         = 0
+	};
+	const struct user_desc npdata16_desc = {
+		.entry_number    = 4,
+		.base_addr       = (unsigned long)stack16,
+		.limit           = 0xffff,
+		.seg_32bit       = 0,
+		.contents        = 0, /* Data, grow-up */
+		.read_exec_only  = 0,
+		.limit_in_pages  = 0,
+		.seg_not_present = 1,
+		.useable         = 0
+	};
 
 	if (syscall(SYS_modify_ldt, 1, &code16_desc, sizeof code16_desc) != 0)
 		err(1, "modify_ldt");
 	if (syscall(SYS_modify_ldt, 1, &data16_desc, sizeof data16_desc) != 0)
 		err(1, "modify_ldt");
+	if (syscall(SYS_modify_ldt, 1, &npcode16_desc, sizeof npcode16_desc) != 0)
+		err(1, "modify_ldt");
+	if (syscall(SYS_modify_ldt, 1, &npdata16_desc, sizeof npdata16_desc) != 0)
+		err(1, "modify_ldt");
 }
 
 static gregset_t initial_regs, requested_regs, resulting_regs;
@@ -144,7 +170,7 @@ static void sigusr1(int sig, siginfo_t *info, void *ctx_void)
 	*ssptr(ctx) = sig_ss;
 
 	ctx->uc_mcontext.gregs[REG_IP] =
-		(sig_cs == 0x7) ? 0 : (unsigned long)&int3;
+		(sig_cs == 0x7 || sig_cs == 0x1f) ? 0 : (unsigned long)&int3;
 	ctx->uc_mcontext.gregs[REG_SP] = (unsigned long)0x8badf00d5aadc0deULL;
 	ctx->uc_mcontext.gregs[REG_AX] = 0;
 
@@ -208,6 +234,7 @@ int cs_bitness(unsigned short cs)
 int find_cs(int bitness)
 {
 	unsigned short my_cs;
+
 	asm ("mov %%cs,%0" :  "=r" (my_cs));
 
 	if (cs_bitness(my_cs) == bitness)
@@ -303,9 +330,9 @@ static int do_test(int cs_bits, bool use_16bit_ss)
 	return nerrs;
 }
 
-static int test_bad_iret(int cs_bits, unsigned short ss)
+static int test_bad_iret(int cs_bits, unsigned short ss, int force_cs)
 {
-	int cs = find_cs(cs_bits);
+	int cs = force_cs == -1 ? find_cs(cs_bits) : force_cs;
 	if (cs == -1)
 		return 0;
 
@@ -329,9 +356,10 @@ static int test_bad_iret(int cs_bits, unsigned short ss)
 int main()
 {
 	int total_nerrs = 0;
-	unsigned short my_cs;
+	unsigned short my_cs, my_ss;
 
 	asm volatile ("mov %%cs,%0" : "=r" (my_cs));
+	asm volatile ("mov %%ss,%0" : "=r" (my_ss));
 	setup_ldt();
 
 	stack_t stack = {
@@ -354,13 +382,19 @@ int main()
 	clearhandler(SIGTRAP);
 	sethandler(SIGSEGV, sigtrap, SA_ONSTACK);
 
-	test_bad_iret(64, (2 << 3) | 7);
-	test_bad_iret(32, (2 << 3) | 7);
-	test_bad_iret(16, (2 << 3) | 7);
+	test_bad_iret(64, (2 << 3) | 7, -1);
+	test_bad_iret(32, (2 << 3) | 7, -1);
+	test_bad_iret(16, (2 << 3) | 7, -1);
+
+	test_bad_iret(64, my_cs, -1);
+	test_bad_iret(32, my_cs, -1);
+	test_bad_iret(16, my_cs, -1);
+
+	/* IRET will fail with #NP */
+	test_bad_iret(32, my_ss, (3 << 3) | 7);
 
-	test_bad_iret(64, my_cs);
-	test_bad_iret(32, my_cs);
-	test_bad_iret(16, my_cs);
+	/* IRET will fail with #SS */
+	test_bad_iret(32, (4 << 3) | 7, -1);
 
 	return total_nerrs ? 1 : 0;
 }