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)); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
