diff options
author | Eric W. Biederman <ebiederm@xmission.com> | 2018-01-03 19:22:04 -0600 |
---|---|---|
committer | Eric W. Biederman <ebiederm@xmission.com> | 2018-09-19 15:53:11 +0200 |
commit | 8d68fa0e083995b48be6b66e04afe746d4654b0c (patch) | |
tree | 6c939685f89f57cbc13b178c0310c79b98db4072 | |
parent | 8a35eb22c02baf0c58b44ba28fc163270ef147f8 (diff) | |
download | op-kernel-dev-8d68fa0e083995b48be6b66e04afe746d4654b0c.zip op-kernel-dev-8d68fa0e083995b48be6b66e04afe746d4654b0c.tar.gz |
signal/x86: Move mpx siginfo generation into do_bounds
This separates the logic of generating the signal from the logic of
gathering the information about the bounds violation.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
-rw-r--r-- | arch/x86/include/asm/mpx.h | 12 | ||||
-rw-r--r-- | arch/x86/kernel/traps.c | 19 | ||||
-rw-r--r-- | arch/x86/mm/mpx.c | 30 |
3 files changed, 32 insertions, 29 deletions
diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h index 61eb4b6..d0b1434 100644 --- a/arch/x86/include/asm/mpx.h +++ b/arch/x86/include/asm/mpx.h @@ -57,8 +57,14 @@ #define MPX_BNDCFG_ADDR_MASK (~((1UL<<MPX_BNDCFG_TAIL)-1)) #define MPX_BNDSTA_ERROR_CODE 0x3 +struct mpx_fault_info { + void __user *addr; + void __user *lower; + void __user *upper; +}; + #ifdef CONFIG_X86_INTEL_MPX -siginfo_t *mpx_generate_siginfo(struct pt_regs *regs); +int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs); int mpx_handle_bd_fault(void); static inline int kernel_managing_mpx_tables(struct mm_struct *mm) { @@ -78,9 +84,9 @@ void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long mpx_unmapped_area_check(unsigned long addr, unsigned long len, unsigned long flags); #else -static inline siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) +static inline int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs) { - return NULL; + return -EINVAL; } static inline int mpx_handle_bd_fault(void) { diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index e6db475..2155d2c 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -455,7 +455,6 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) { const struct mpx_bndcsr *bndcsr; - siginfo_t *info; RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU"); if (notify_die(DIE_TRAP, "bounds", regs, error_code, @@ -493,8 +492,11 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) goto exit_trap; break; /* Success, it was handled */ case 1: /* Bound violation. */ - info = mpx_generate_siginfo(regs); - if (IS_ERR(info)) { + { + struct mpx_fault_info mpx; + struct siginfo info; + + if (mpx_fault_info(&mpx, regs)) { /* * We failed to decode the MPX instruction. Act as if * the exception was not caused by MPX. @@ -508,9 +510,16 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) * allows and application to possibly handle the * #BR exception itself. */ - do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, info); - kfree(info); + clear_siginfo(&info); + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = SEGV_BNDERR; + info.si_addr = mpx.addr; + info.si_lower = mpx.lower; + info.si_upper = mpx.upper; + do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, &info); break; + } case 0: /* No exception caused by Intel MPX operations. */ goto exit_trap; default: diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index e500949..2385538 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -118,14 +118,11 @@ bad_opcode: * anything it wants in to the instructions. We can not * trust anything about it. They might not be valid * instructions or might encode invalid registers, etc... - * - * The caller is expected to kfree() the returned siginfo_t. */ -siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) +int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs) { const struct mpx_bndreg_state *bndregs; const struct mpx_bndreg *bndreg; - siginfo_t *info = NULL; struct insn insn; uint8_t bndregno; int err; @@ -153,11 +150,6 @@ siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) /* now go select the individual register in the set of 4 */ bndreg = &bndregs->bndreg[bndregno]; - info = kzalloc(sizeof(*info), GFP_KERNEL); - if (!info) { - err = -ENOMEM; - goto err_out; - } /* * The registers are always 64-bit, but the upper 32 * bits are ignored in 32-bit mode. Also, note that the @@ -168,27 +160,23 @@ siginfo_t *mpx_generate_siginfo(struct pt_regs *regs) * complains when casting from integers to different-size * pointers. */ - info->si_lower = (void __user *)(unsigned long)bndreg->lower_bound; - info->si_upper = (void __user *)(unsigned long)~bndreg->upper_bound; - info->si_addr_lsb = 0; - info->si_signo = SIGSEGV; - info->si_errno = 0; - info->si_code = SEGV_BNDERR; - info->si_addr = insn_get_addr_ref(&insn, regs); + info->lower = (void __user *)(unsigned long)bndreg->lower_bound; + info->upper = (void __user *)(unsigned long)~bndreg->upper_bound; + info->addr = insn_get_addr_ref(&insn, regs); + /* * We were not able to extract an address from the instruction, * probably because there was something invalid in it. */ - if (info->si_addr == (void __user *)-1) { + if (info->addr == (void __user *)-1) { err = -EINVAL; goto err_out; } - trace_mpx_bounds_register_exception(info->si_addr, bndreg); - return info; + trace_mpx_bounds_register_exception(info->addr, bndreg); + return 0; err_out: /* info might be NULL, but kfree() handles that */ - kfree(info); - return ERR_PTR(err); + return err; } static __user void *mpx_get_bounds_dir(void) |