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| author | Andy Lutomirski <luto@kernel.org> | 2018-11-21 15:11:23 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-11-22 09:23:00 +0100 |
| commit | ebb53e2597e2dc7637ab213df006e99681b6ee25 (patch) | |
| tree | f1e44cb1be25f02be829d87760fbc8e3d82043c3 /arch/x86/mm/fault.c | |
| parent | 0ed32f1aa66ee758e6c8164f549f7ff9d399a20e (diff) | |
| download | lwn-ebb53e2597e2dc7637ab213df006e99681b6ee25.tar.gz lwn-ebb53e2597e2dc7637ab213df006e99681b6ee25.zip | |
x86/fault: Don't try to recover from an implicit supervisor access
This avoids a situation in which we attempt to apply various fixups
that are not intended to handle implicit supervisor accesses from
user mode if we screw up in a way that causes this type of fault.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/9999f151d72ff352265f3274c5ab3a4105090f49.1542841400.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 82881bc5feef..ca38bd0472f2 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -653,6 +653,15 @@ no_context(struct pt_regs *regs, unsigned long error_code, unsigned long flags; int sig; + if (user_mode(regs)) { + /* + * This is an implicit supervisor-mode access from user + * mode. Bypass all the kernel-mode recovery code and just + * OOPS. + */ + goto oops; + } + /* Are we prepared to handle this kernel fault? */ if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) { /* @@ -738,6 +747,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, if (IS_ENABLED(CONFIG_EFI)) efi_recover_from_page_fault(address); +oops: /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice: |