svn commit: r359974 - head/sys/mips/mips
Brooks Davis
brooks at FreeBSD.org
Wed Apr 15 16:33:28 UTC 2020
Author: brooks
Date: Wed Apr 15 16:33:27 2020
New Revision: 359974
URL: https://svnweb.freebsd.org/changeset/base/359974
Log:
Don't directly access userspace memory.
Rather then using the racy useracc() followed by direct access to
userspace memory, perform a copyin() and use the result if it succeeds.
Reviewed by: jhb
MFC after: 3 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24410
Modified:
head/sys/mips/mips/trap.c
Modified: head/sys/mips/mips/trap.c
==============================================================================
--- head/sys/mips/mips/trap.c Wed Apr 15 14:07:33 2020 (r359973)
+++ head/sys/mips/mips/trap.c Wed Apr 15 16:33:27 2020 (r359974)
@@ -1402,7 +1402,7 @@ log_illegal_instruction(const char *msg, struct trapfr
{
pt_entry_t *ptep;
pd_entry_t *pdep;
- unsigned int *addr;
+ unsigned int *addr, instr[4];
struct thread *td;
struct proc *p;
register_t pc;
@@ -1429,17 +1429,16 @@ log_illegal_instruction(const char *msg, struct trapfr
* Dump a few words around faulting instruction, if the addres is
* valid.
*/
- if (!(pc & 3) &&
- useracc((caddr_t)(intptr_t)pc, sizeof(int) * 4, VM_PROT_READ)) {
+ addr = (unsigned int *)(intptr_t)pc;
+ if ((pc & 3) == 0 && copyin(addr, instr, sizeof(instr)) == 0) {
/* dump page table entry for faulting instruction */
log(LOG_ERR, "Page table info for pc address %#jx: pde = %p, pte = %#jx\n",
(intmax_t)pc, (void *)(intptr_t)*pdep, (uintmax_t)(ptep ? *ptep : 0));
- addr = (unsigned int *)(intptr_t)pc;
log(LOG_ERR, "Dumping 4 words starting at pc address %p: \n",
addr);
log(LOG_ERR, "%08x %08x %08x %08x\n",
- addr[0], addr[1], addr[2], addr[3]);
+ instr[0], instr[1], instr[2], instr[3]);
} else {
log(LOG_ERR, "pc address %#jx is inaccessible, pde = %p, pte = %#jx\n",
(intmax_t)pc, (void *)(intptr_t)*pdep, (uintmax_t)(ptep ? *ptep : 0));
@@ -1451,7 +1450,7 @@ log_bad_page_fault(char *msg, struct trapframe *frame,
{
pt_entry_t *ptep;
pd_entry_t *pdep;
- unsigned int *addr;
+ unsigned int *addr, instr[4];
struct thread *td;
struct proc *p;
char *read_or_write;
@@ -1499,18 +1498,18 @@ log_bad_page_fault(char *msg, struct trapframe *frame,
* Dump a few words around faulting instruction, if the addres is
* valid.
*/
- if (!(pc & 3) && (pc != frame->badvaddr) &&
- (trap_type != T_BUS_ERR_IFETCH) &&
- useracc((caddr_t)(intptr_t)pc, sizeof(int) * 4, VM_PROT_READ)) {
+ addr = (unsigned int *)(intptr_t)pc;
+ if ((pc & 3) == 0 && pc != frame->badvaddr &&
+ trap_type != T_BUS_ERR_IFETCH &&
+ copyin((caddr_t)(intptr_t)pc, instr, sizeof(instr)) == 0) {
/* dump page table entry for faulting instruction */
log(LOG_ERR, "Page table info for pc address %#jx: pde = %p, pte = %#jx\n",
(intmax_t)pc, (void *)(intptr_t)*pdep, (uintmax_t)(ptep ? *ptep : 0));
- addr = (unsigned int *)(intptr_t)pc;
log(LOG_ERR, "Dumping 4 words starting at pc address %p: \n",
addr);
log(LOG_ERR, "%08x %08x %08x %08x\n",
- addr[0], addr[1], addr[2], addr[3]);
+ instr[0], instr[1], instr[2], instr[3]);
} else {
log(LOG_ERR, "pc address %#jx is inaccessible, pde = %p, pte = %#jx\n",
(intmax_t)pc, (void *)(intptr_t)*pdep, (uintmax_t)(ptep ? *ptep : 0));
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