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x86/mm/pkeys: Fix fill_sig_info_pkey 

SEGV_PKUERR is a signal specific si_code which happens to have the
same numeric value as several others: BUS_MCEERR_AR, ILL_ILLTRP,
FPE_FLTOVF, TRAP_HWBKPT, CLD_TRAPPED, POLL_ERR, SEGV_THREAD_ID,
as such it is not safe to just test the si_code the signal number
must also be tested to prevent a false positive in fill_sig_info_pkey.

I found this error by inspection, and BUS_MCEERR_AR appears to
be a real candidate for confusion.  So pass in si_signo and fix it.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Fixes: 019132ff3d ("x86/mm/pkeys: Fill in pkey field in siginfo")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2018-01-03 19:04:34 -06:00
parent 6ac1dc736b
commit 90bc9fb159
1 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/x86/mm/fault.c
View File

@ -172,14 +172,15 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
* 6. T1 : reaches here, sees vma_pkey(vma)=5, when we really
* faulted on a pte with its pkey=4.
*/
static void fill_sig_info_pkey(int si_code, siginfo_t *info, u32 *pkey)
static void fill_sig_info_pkey(int si_signo, int si_code, siginfo_t *info,
u32 *pkey)
{
/* This is effectively an #ifdef */
if (!boot_cpu_has(X86_FEATURE_OSPKE))
return;
/* Fault not from Protection Keys: nothing to do */
if (si_code != SEGV_PKUERR)
if ((si_code != SEGV_PKUERR) || (si_signo != SIGSEGV))
return;
/*
* force_sig_info_fault() is called from a number of
@ -218,7 +219,7 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
lsb = PAGE_SHIFT;
info.si_addr_lsb = lsb;
fill_sig_info_pkey(si_code, &info, pkey);
fill_sig_info_pkey(si_signo, si_code, &info, pkey);
force_sig_info(si_signo, &info, tsk);
}