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authorKees Cook <keescook@chromium.org>2016-08-18 00:42:11 +0300
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2016-10-31 23:01:58 +0300
commitde54ebbe26bb371a6f1fbc0593372232f04e3107 (patch)
tree41550879530d6752373feb43eba0d53f39a063a2 /include/linux/bug.h
parent0cd340dcb05c4a43742fe156f36737bb2a321bfd (diff)
downloadlinux-de54ebbe26bb371a6f1fbc0593372232f04e3107.tar.xz
bug: Provide toggle for BUG on data corruption
The kernel checks for cases of data structure corruption under some CONFIGs (e.g. CONFIG_DEBUG_LIST). When corruption is detected, some systems may want to BUG() immediately instead of letting the system run with known corruption. Usually these kinds of manipulation primitives can be used by security flaws to gain arbitrary memory write control. This provides a new config CONFIG_BUG_ON_DATA_CORRUPTION and a corresponding macro CHECK_DATA_CORRUPTION for handling these situations. Notably, even if not BUGing, the kernel should not continue processing the corrupted structure. This is inspired by similar hardening by Syed Rameez Mustafa in MSM kernels, and in PaX and Grsecurity, which is likely in response to earlier removal of the BUG calls in commit 924d9addb9b1 ("list debugging: use WARN() instead of BUG()"). Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Rik van Riel <riel@redhat.com>
Diffstat (limited to 'include/linux/bug.h')
-rw-r--r--include/linux/bug.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/bug.h b/include/linux/bug.h
index 292d6a10b0c2..baff2e8fc8a8 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -121,4 +121,21 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr,
}
#endif /* CONFIG_GENERIC_BUG */
+
+/*
+ * Since detected data corruption should stop operation on the affected
+ * structures, this returns false if the corruption condition is found.
+ */
+#define CHECK_DATA_CORRUPTION(condition, fmt, ...) \
+ do { \
+ if (unlikely(condition)) { \
+ if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
+ pr_err(fmt, ##__VA_ARGS__); \
+ BUG(); \
+ } else \
+ WARN(1, fmt, ##__VA_ARGS__); \
+ return false; \
+ } \
+ } while (0)
+
#endif /* _LINUX_BUG_H */