Messages in this thread Patch in this message | | | From | William Cohen <> | Subject | [PATCH] Check jvmti_agent snprintf return value to avoid build failures with GCC-8.1.1 | Date | Tue, 10 Jul 2018 14:27:16 -0400 |
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Newer versions of GCC perform static analysis to determine whether string truncation is possible with functions such as snprintf and provide a warning if truncation could occur. The make for jvmti_agent.c uses the compiler option that treats any compiler warnings as compiler errors. For GCC-8.1.1 in Fedora 28 this causes the build to fail. The return value of the snprint is now checked to ensure snprintf produced a NULL-terminated string. If the string for the path is invalid, the code does attempt to use the string.
Signed-off-by: William Cohen <wcohen@redhat.com> --- tools/perf/jvmti/jvmti_agent.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c index 0c6d1002b524..30f14eafe4b3 100644 --- a/tools/perf/jvmti/jvmti_agent.c +++ b/tools/perf/jvmti/jvmti_agent.c @@ -227,7 +227,7 @@ void *jvmti_open(void) { char dump_path[PATH_MAX]; struct jitheader header; - int fd; + int retlen, fd; FILE *fp; init_arch_timestamp(); @@ -249,7 +249,10 @@ void *jvmti_open(void) /* * jitdump file name */ - snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid()); + retlen = snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", + jit_path, getpid()); + if (retlen <= 0 || ((int) sizeof(dump_path)) <= retlen) + return NULL; fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666); if (fd == -1) -- 2.17.1
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