From 6e6c21c894904d5d9ce75f1a56e4fa5f82b199c1 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 14 May 2015 11:30:59 +0200 Subject: util: introduce memmem_safe() and make use of it GNU memmem() requires a nonnull first parameter. Let's introduce memmem_safe() that removes this restriction for zero-length parameters, and make use of it where appropriate. http://lists.freedesktop.org/archives/systemd-devel/2015-May/031705.html --- src/libsystemd/sd-bus/bus-socket.c | 2 +- src/shared/util.h | 15 +++++++++++++++ 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c index 94a5c04c8b..24b9c4d117 100644 --- a/src/libsystemd/sd-bus/bus-socket.c +++ b/src/libsystemd/sd-bus/bus-socket.c @@ -177,7 +177,7 @@ static int bus_socket_auth_verify_client(sd_bus *b) { /* We expect two response lines: "OK" and possibly * "AGREE_UNIX_FD" */ - e = memmem(b->rbuffer, b->rbuffer_size, "\r\n", 2); + e = memmem_safe(b->rbuffer, b->rbuffer_size, "\r\n", 2); if (!e) return 0; diff --git a/src/shared/util.h b/src/shared/util.h index 637934fecc..0c81e3dc45 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -787,6 +787,21 @@ static inline void qsort_safe(void *base, size_t nmemb, size_t size, comparison_ qsort(base, nmemb, size, compar); } +/* Normal memmem() requires haystack to be nonnull, which is annoying for zero-length buffers */ +static inline void *memmem_safe(const void *haystack, size_t haystacklen, const void *needle, size_t needlelen) { + + if (needlelen <= 0) + return (void*) haystack; + + if (haystacklen < needlelen) + return NULL; + + assert(haystack); + assert(needle); + + return memmem(haystack, haystacklen, needle, needlelen); +} + int proc_cmdline(char **ret); int parse_proc_cmdline(int (*parse_word)(const char *key, const char *value)); int get_proc_cmdline_key(const char *parameter, char **value); -- cgit v1.2.3-54-g00ecf