3.2.67-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Andy Lutomirski <l...@amacapital.net> commit e30ab185c490e9a9381385529e0fd32f0a399495 upstream. 32-bit programs don't have an lm bit in their ABI, so they can't reliably cause LDT_empty to return true without resorting to memset. They shouldn't need to do this. This should fix a longstanding, if minor, issue in all 64-bit kernels as well as a potential regression in the TLS hardening code. Fixes: 41bdc78544b8 x86/tls: Validate TLS entries to protect espfix Signed-off-by: Andy Lutomirski <l...@amacapital.net> Cc: torva...@linux-foundation.org Link: http://lkml.kernel.org/r/72a059de55e86ad5e2935c80aa91880ddf19d07c.1421954363.git.l...@amacapital.net Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Ben Hutchings <b...@decadent.org.uk> --- arch/x86/include/asm/desc.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -248,7 +248,8 @@ static inline void native_load_tls(struc gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]; } -#define _LDT_empty(info) \ +/* This intentionally ignores lm, since 32-bit apps don't have that field. */ +#define LDT_empty(info) \ ((info)->base_addr == 0 && \ (info)->limit == 0 && \ (info)->contents == 0 && \ @@ -258,12 +259,6 @@ static inline void native_load_tls(struc (info)->seg_not_present == 1 && \ (info)->useable == 0) -#ifdef CONFIG_X86_64 -#define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0)) -#else -#define LDT_empty(info) (_LDT_empty(info)) -#endif - static inline void clear_LDT(void) { set_ldt(NULL, 0); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
