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authorThomas Garnier <thgarnie@google.com>2017-09-07 08:30:44 -0700
committerThomas Gleixner <tglx@linutronix.de>2017-09-17 19:45:32 +0200
commitbf29ed1567b67854dc13504f685c45a2ea9b2081 (patch)
tree74bc82cb10d5af8b006ab4b9e06f3f1d6e8a12b8 /include
parent0666f560b71b899cd11a7caf39fd45129e9030fd (diff)
downloadlinux-bf29ed1567b67854dc13504f685c45a2ea9b2081.tar.bz2
syscalls: Use CHECK_DATA_CORRUPTION for addr_limit_user_check
Use CHECK_DATA_CORRUPTION instead of BUG_ON to provide more flexibility on address limit failures. By default, send a SIGKILL signal to kill the current process preventing exploitation of a bad address limit. Make the TIF_FSCHECK flag optional so ARM can use this function. Signed-off-by: Thomas Garnier <thgarnie@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Pratyush Anand <panand@redhat.com> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Will Drewry <wad@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Andy Lutomirski <luto@amacapital.net> Cc: David Howells <dhowells@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-api@vger.kernel.org Cc: Yonghong Song <yhs@fb.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1504798247-48833-2-git-send-email-keescook@chromium.org
Diffstat (limited to 'include')
-rw-r--r--include/linux/syscalls.h12
1 files changed, 8 insertions, 4 deletions
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 95606a2d556f..a78186d826d7 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -221,21 +221,25 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
} \
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
-#ifdef TIF_FSCHECK
/*
* Called before coming back to user-mode. Returning to user-mode with an
* address limit different than USER_DS can allow to overwrite kernel memory.
*/
static inline void addr_limit_user_check(void)
{
-
+#ifdef TIF_FSCHECK
if (!test_thread_flag(TIF_FSCHECK))
return;
+#endif
- BUG_ON(!segment_eq(get_fs(), USER_DS));
+ if (CHECK_DATA_CORRUPTION(!segment_eq(get_fs(), USER_DS),
+ "Invalid address limit on user-mode return"))
+ force_sig(SIGKILL, current);
+
+#ifdef TIF_FSCHECK
clear_thread_flag(TIF_FSCHECK);
-}
#endif
+}
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
qid_t id, void __user *addr);