diff options
| author | Daniel Thompson <daniel.thompson@linaro.org> | 2020-09-28 00:15:29 +0300 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2020-09-28 14:14:08 +0300 |
| commit | f2d10ff4a903813df767a4b56b651a26b938df06 (patch) | |
| tree | a6969351434aa9c2eac82e8bec42115a01df2507 /include/linux/kgdb.h | |
| parent | e16c33e290792c9b71b952dc915e5f7dfc9d4409 (diff) | |
| download | linux-f2d10ff4a903813df767a4b56b651a26b938df06.tar.xz | |
kgdb: Honour the kprobe blocklist when setting breakpoints
Currently kgdb has absolutely no safety rails in place to discourage or
prevent a user from placing a breakpoint in dangerous places such as
the debugger's own trap entry/exit and other places where it is not safe
to take synchronous traps.
Introduce a new config symbol KGDB_HONOUR_BLOCKLIST and modify the
default implementation of kgdb_validate_break_address() so that we use
the kprobe blocklist to prohibit instrumentation of critical functions
if the config symbol is set. The config symbol dependencies are set to
ensure that the blocklist will be enabled by default if we enable KGDB
and are compiling for an architecture where we HAVE_KPROBES.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20200927211531.1380577-2-daniel.thompson@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Diffstat (limited to 'include/linux/kgdb.h')
| -rw-r--r-- | include/linux/kgdb.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 477b8b7c908f..0d6cf64c8bb1 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -16,6 +16,7 @@ #include <linux/linkage.h> #include <linux/init.h> #include <linux/atomic.h> +#include <linux/kprobes.h> #ifdef CONFIG_HAVE_ARCH_KGDB #include <asm/kgdb.h> #endif @@ -335,6 +336,23 @@ extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, atomic_t *snd_rdy); extern void gdbstub_exit(int status); +/* + * kgdb and kprobes both use the same (kprobe) blocklist (which makes sense + * given they are both typically hooked up to the same trap meaning on most + * architectures one cannot be used to debug the other) + * + * However on architectures where kprobes is not (yet) implemented we permit + * breakpoints everywhere rather than blocking everything by default. + */ +static inline bool kgdb_within_blocklist(unsigned long addr) +{ +#ifdef CONFIG_KGDB_HONOUR_BLOCKLIST + return within_kprobe_blacklist(addr); +#else + return false; +#endif +} + extern int kgdb_single_step; extern atomic_t kgdb_active; #define in_dbg_master() \ |