diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2016-07-01 18:22:39 +0100 |
|---|---|---|
| committer | Sami Tolvanen <samitolvanen@google.com> | 2016-09-29 10:52:56 -0700 |
| commit | 5dc2b7c7bb33138270ff9494be6cf334bd3d20e1 (patch) | |
| tree | b4b3a4cda7deb43d0fa1e461e1bd82e63bd3f541 /arch | |
| parent | 5775ca34829caf0664c8ccc02fd0e93cb6022e0f (diff) | |
FROMLIST: arm64: Handle faults caused by inadvertent user access with PAN enabled
When TTBR0_EL1 is set to the reserved page, an erroneous kernel access
to user space would generate a translation fault. This patch adds the
checks for the software-set PSR_PAN_BIT to emulate a permission fault
and report it accordingly.
This patch also updates the description of the synchronous external
aborts on translation table walks.
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Change-Id: I623113fc8bf6d5f023aeec7a0640b62a25ef8420
(cherry picked from commit be3db9340c8011d22f06715339b66bcbbd4893bd)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/mm/fault.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index e328430dbcec..f0c75fd6a3fa 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -246,13 +246,19 @@ out: return fault; } -static inline bool is_permission_fault(unsigned int esr) +static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs) { unsigned int ec = ESR_ELx_EC(esr); unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; - return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM) || - (ec == ESR_ELx_EC_IABT_CUR && fsc_type == ESR_ELx_FSC_PERM); + if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR) + return false; + + if (system_uses_ttbr0_pan()) + return fsc_type == ESR_ELx_FSC_FAULT && + (regs->pstate & PSR_PAN_BIT); + else + return fsc_type == ESR_ELx_FSC_PERM; } static bool is_el0_instruction_abort(unsigned int esr) @@ -293,7 +299,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, mm_flags |= FAULT_FLAG_WRITE; } - if (is_permission_fault(esr) && (addr < USER_DS)) { + if (addr < USER_DS && is_permission_fault(esr, regs)) { /* regs->orig_addr_limit may be 0 if we entered from EL0 */ if (regs->orig_addr_limit == KERNEL_DS) die("Accessing user space memory with fs=KERNEL_DS", regs, esr); @@ -478,10 +484,10 @@ static const struct fault_info { { do_bad, SIGBUS, 0, "unknown 17" }, { do_bad, SIGBUS, 0, "unknown 18" }, { do_bad, SIGBUS, 0, "unknown 19" }, - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous external abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous external abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous external abort (translation table walk)" }, + { do_bad, SIGBUS, 0, "synchronous external abort (translation table walk)" }, { do_bad, SIGBUS, 0, "synchronous parity error" }, { do_bad, SIGBUS, 0, "unknown 25" }, { do_bad, SIGBUS, 0, "unknown 26" }, |