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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-19 13:18:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-19 13:18:31 -0800 |
| commit | 1092b596a56b6ac5fa3154dc75bfcbb6f27ac757 (patch) | |
| tree | a804de50bae89bba47aaa414e6a4fb033da0dd94 | |
| parent | 88a57667f2990f00b019d46c8426441c9e516d51 (diff) | |
| parent | 3fb2f4237bb452eb4e98f6a5dbd5a445b4fed9d0 (diff) | |
| download | linux-1092b596a56b6ac5fa3154dc75bfcbb6f27ac757.tar.gz | |
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Ingo Molnar: "This contains a single TLS ABI validation fix from Andy Lutomirski" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tls: Don't validate lm in set_thread_area() after all
| -rw-r--r-- | arch/x86/include/uapi/asm/ldt.h | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/tls.c | 6 |
2 files changed, 7 insertions, 6 deletions
diff --git a/arch/x86/include/uapi/asm/ldt.h b/arch/x86/include/uapi/asm/ldt.h index 46727eb37bfe..6e1aaf73852a 100644 --- a/arch/x86/include/uapi/asm/ldt.h +++ b/arch/x86/include/uapi/asm/ldt.h @@ -28,6 +28,13 @@ struct user_desc { unsigned int seg_not_present:1; unsigned int useable:1; #ifdef __x86_64__ + /* + * Because this bit is not present in 32-bit user code, user + * programs can pass uninitialized values here. Therefore, in + * any context in which a user_desc comes from a 32-bit program, + * the kernel must act as though lm == 0, regardless of the + * actual value. + */ unsigned int lm:1; #endif }; diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c index 3e551eee87b9..4e942f31b1a7 100644 --- a/arch/x86/kernel/tls.c +++ b/arch/x86/kernel/tls.c @@ -55,12 +55,6 @@ static bool tls_desc_okay(const struct user_desc *info) if (info->seg_not_present) return false; -#ifdef CONFIG_X86_64 - /* The L bit makes no sense for data. */ - if (info->lm) - return false; -#endif - return true; } |