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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Aug 09, 2019 at 01:20:45PM +0100, Cristian Marussi wrote: > > Hi > > On 8/9/19 12:16 PM, Dave Martin wrote: > >On Fri, Aug 09, 2019 at 11:54:06AM +0100, Cristian Marussi wrote: > >>Hi > >> > >>On 8/2/19 6:02 PM, Cristian Marussi wrote: > >>>Added some arm64/signal specific boilerplate and utility code to help > >>>further testcase development. > >>> > >>>A simple testcase and related helpers are also introduced in this commit: > >>>mangle_pstate_invalid_compat_toggle is a simple mangle testcase which > >>>messes with the ucontext_t from within the sig_handler, trying to toggle > >>>PSTATE state bits to switch the system between 32bit/64bit execution state. > >>>Expects SIGSEGV on test PASS. > >>> > >>>Signed-off-by: Cristian Marussi > >>>--- [...] > >>diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c > >>index 31788a1d33a4..c0f3cd1b560a 100644 > >>--- a/tools/testing/selftests/arm64/signal/test_signals_utils.c > >>+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c > >>@@ -23,21 +23,25 @@ extern struct tdescr *current; > >> static int sig_copyctx = SIGTRAP; > >> static char *feats_store[FMAX_END] = { > >>- "SSBS", > >>- "PAN", > >>- "UAO", > >>+ " SSBS ", > >>+ " PAN ", > >>+ " UAO ", > >> }; > >> #define MAX_FEATS_SZ 128 > >>+static char feats_string[MAX_FEATS_SZ]; > >>+ > >> static inline char *feats_to_string(unsigned long feats) > >> { > >>- static char feats_string[MAX_FEATS_SZ]; > >>+ for (int i = 0; i < FMAX_END; i++) { > >>+ size_t tlen = 0; > >>- for (int i = 0; i < FMAX_END && feats_store[i][0]; i++) { > >>- if (feats & 1UL << i) > >>- snprintf(feats_string, MAX_FEATS_SZ - 1, "%s %s ", > >>- feats_string, feats_store[i]); > >>+ if (feats & 1UL << i) { > >>+ strncat(feats_string, feats_store[i], > > > >Should this be feats_string + tlen? > > > > strncat appends to the end of a NULL terminated string overwriting the NULL itself and > appending its own NULL (as long as dest and src do not overlap and fits the max size param), > so it must be fed the start of the dest string to which we are appending > > >>+ MAX_FEATS_SZ - 1 - tlen); I see. Yes, you're right -- I was confusing strncat() with strncpy(). > >An assert(tlen <= MAX_FEATS_SZ - 1) is probably a good idea here, > >in case more features are added to feats_store[] someday. > > > > Yes in fact...if not it would be simply truncated silently I think MAX_FEATS - 1 - tlen would overflow. tlen is a size_t, so the result would might be a giant unsigned number in this case, leading to a potential buffer overrun in strncat(). > > >>+ tlen += strlen(feats_store[i]); > >>+ } > > > >Don't we need to initialise tlen outside the loop? Otherwise we just > >zero it again after the +=. > > ..and that's a bug :< OK > > > >> } > >> return feats_string; > >>@@ -190,7 +194,7 @@ static void default_handler(int signum, siginfo_t *si, void *uc) > >> /* it's a bug in the test code when this assert fail */ > >> assert(!current->sig_trig || current->triggered); > >> fprintf(stderr, > >>- "SIG_OK -- SP:%p si_addr@:0x%p si_code:%d token@:0x%p offset:%ld\n", > >>+ "SIG_OK -- SP:%llX si_addr@:0x%p si_code:%d token@:0x%p offset:%ld\n", > > > >For consistency, can we have a "0x" prefix? > > > >I think %p usually generates a "0x" prefix by itself, so 0x%p might give > >a double prefix. > > > > Yes you are right. > > Moreover I'm in doubt what to do generally with all these stderr > output, because I optionally discard to null testing standalone, but > this is not what the KSFT framework runner script does, so > arm64/signal tests end up being overly verbose when run from the > framework (even if tests use anyway the KSFT exit codes conventions > so all the results are correctly reported); but I suppose I'll > receive a clear indication on this matter from the maintainers at the > end... Sure, keep the prints for now. If they're potentially useful we can always find a way to make them optional. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel