Fix bug where memory was being used instead of extram when reading cstring from extram

This commit is contained in:
Toby Jaffey 2025-12-13 18:46:28 +00:00
parent 8a0604fc8d
commit b1b4cbf583
4 changed files with 101 additions and 7 deletions

View file

@ -61,6 +61,14 @@ void main(void) {
p[5] = '\0'; p[5] = '\0';
println(p); // try to print from extram (terminated) println(p); // try to print from extram (terminated)
} break; } break;
case TEST11: {
// pass a string beyond end of ram
println((uint32_t)0xFFFFFFFF);
} break;
case TEST12: {
// pass a string beyond end of MMIO region
println((uint32_t)UVM32_EXTRAM_BASE + 8); // extram has been shrunk, this is now out of bounds, or no terminator found
} break;
} }
} }

View file

@ -12,5 +12,7 @@ enum {
TEST8, TEST8,
TEST9, TEST9,
TEST10, TEST10,
TEST11,
TEST12,
}; };

View file

@ -217,13 +217,13 @@ void test_extram_buf_terminated(void) {
// check for picktest syscall // check for picktest syscall
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL); TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL);
TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST); TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST);
uvm32_arg_setval(&vmst, &evt, RET, TEST9); uvm32_arg_setval(&vmst, &evt, RET, TEST10);
uvm32_run(&vmst, &evt, 100); uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(true, uvm32_extramDirty(&vmst)); TEST_ASSERT_EQUAL(true, uvm32_extramDirty(&vmst));
// check for printbuf of val // check for printbuf of val
TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ); TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ);
TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTBUF); TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTLN);
const char *str = uvm32_arg_getcstr(&vmst, &evt, ARG0); const char *str = uvm32_arg_getcstr(&vmst, &evt, ARG0);
TEST_ASSERT_NOT_EQUAL(NULL, str); TEST_ASSERT_NOT_EQUAL(NULL, str);
TEST_ASSERT_EQUAL(0, strcmp(str, "hello")); TEST_ASSERT_EQUAL(0, strcmp(str, "hello"));
@ -237,13 +237,13 @@ void test_extram_buf_terminated_rugpull(void) {
// check for picktest syscall // check for picktest syscall
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL); TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL);
TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST); TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST);
uvm32_arg_setval(&vmst, &evt, RET, TEST9); uvm32_arg_setval(&vmst, &evt, RET, TEST10);
uvm32_run(&vmst, &evt, 100); uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(true, uvm32_extramDirty(&vmst)); TEST_ASSERT_EQUAL(true, uvm32_extramDirty(&vmst));
// check for printbuf of val // check for printbuf of val
TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ); TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ);
TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTBUF); TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTLN);
// remove extram // remove extram
uvm32_extram(&vmst, NULL, 0); uvm32_extram(&vmst, NULL, 0);
@ -256,4 +256,89 @@ void test_extram_buf_terminated_rugpull(void) {
TEST_ASSERT_EQUAL(evt.data.err.errcode, UVM32_ERR_MEM_RD); TEST_ASSERT_EQUAL(evt.data.err.errcode, UVM32_ERR_MEM_RD);
} }
void test_extram_buf_terminated_beyond_mem_end(void) {
// run the vm
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for picktest syscall
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL);
TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST);
uvm32_arg_setval(&vmst, &evt, RET, TEST11);
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for printbuf of val
TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ);
TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTLN);
// check that reading from non-existent extram gives empty string and puts into err state
const char *str = uvm32_arg_getcstr(&vmst, &evt, ARG0);
TEST_ASSERT_EQUAL(0, strlen(str));
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_ERR);
TEST_ASSERT_EQUAL(evt.data.err.errcode, UVM32_ERR_MEM_RD);
}
void test_extram_buf_terminated_beyond_extram_end_oobstart(void) {
// run the vm
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for picktest syscall
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL);
TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST);
uvm32_arg_setval(&vmst, &evt, RET, TEST12);
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for printbuf of val
TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ);
TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTLN);
// replace extram with a tiny one, so read is off the end
uint32_t r[1];
r[0] = 0xFFFFFFFF; // non zero so string isn't terminated
uvm32_extram(&vmst, (uint8_t *)r, 4);
// check that reading from non-existent extram gives empty string and puts into err state
const char *str = uvm32_arg_getcstr(&vmst, &evt, ARG0);
TEST_ASSERT_EQUAL(0, strlen(str));
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_ERR);
TEST_ASSERT_EQUAL(evt.data.err.errcode, UVM32_ERR_MEM_RD);
}
void test_extram_buf_terminated_beyond_extram_end(void) {
// run the vm
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for picktest syscall
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_SYSCALL);
TEST_ASSERT_EQUAL(evt.data.syscall.code, SYSCALL_PICKTEST);
uvm32_arg_setval(&vmst, &evt, RET, TEST12);
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(false, uvm32_extramDirty(&vmst));
// check for printbuf of val
TEST_ASSERT_EQUAL(UVM32_EVT_SYSCALL, evt.typ);
TEST_ASSERT_EQUAL(evt.data.syscall.code, UVM32_SYSCALL_PRINTLN);
// replace extram with a tiny one, so read is off the end
uint32_t r[3];
// non-zero so string never terminates
memset(r, 0xAA, sizeof(r));
uvm32_extram(&vmst, (uint8_t *)r, sizeof(r));
// string starts in valid extram, but no terminator will be found before hitting end of extram
// check that reading from non-existent extram gives empty string and puts into err state
const char *str = uvm32_arg_getcstr(&vmst, &evt, ARG0);
TEST_ASSERT_EQUAL(0, strlen(str));
uvm32_run(&vmst, &evt, 100);
TEST_ASSERT_EQUAL(evt.typ, UVM32_EVT_ERR);
TEST_ASSERT_EQUAL(evt.data.err.errcode, UVM32_ERR_MEM_RD);
}

View file

@ -142,8 +142,7 @@ bool get_safeptr_null_terminated(uvm32_state_t *vmst, uint32_t addr, uvm32_slice
if (vmst->_extram == NULL) { if (vmst->_extram == NULL) {
return false; return false;
} else { } else {
uint32_t ptrstart = addr - UVM32_EXTRAM_BASE;
uint32_t ptrstart = addr - UVM32_EXTRAM_BASE;;
uint32_t p = ptrstart; uint32_t p = ptrstart;
if (p >= vmst->_extramLen) { if (p >= vmst->_extramLen) {
setStatusErr(vmst, UVM32_ERR_MEM_RD); setStatusErr(vmst, UVM32_ERR_MEM_RD);
@ -151,7 +150,7 @@ bool get_safeptr_null_terminated(uvm32_state_t *vmst, uint32_t addr, uvm32_slice
buf->len = 0; buf->len = 0;
return false; return false;
} }
while(vmst->_memory[p] != '\0') { while(vmst->_extram[p] != '\0') {
p++; p++;
if (p >= vmst->_extramLen) { if (p >= vmst->_extramLen) {
setStatusErr(vmst, UVM32_ERR_MEM_RD); setStatusErr(vmst, UVM32_ERR_MEM_RD);