The patch titled Subject: argv_split(): teach it to handle mutable strings has been added to the -mm tree. Its filename is argv_split-teach-it-to-handle-mutable-strings.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: argv_split(): teach it to handle mutable strings argv_split() allocates argv[count_argc(str)] array and assumes that it will find the same number of arguments later. This is obviously wrong if this string can be changed, say, by sysctl. With this patch argv_split() kstrndup's the whole string and does not split it, we simply replace the spaces with zeroes and keep the allocated memory in argv[-1] for argv_free(arg). We do not use argv[0] because: - str can be all-spaces or empty. In fact this case is fine, we could kfree() it before return, but: - str can have a space at the start, and we can not rely on kstrndup(skip_spaces(str)) because it can equally race if this string is mutable. Also, simplify count_argc() and kill the no longer used skip_arg(). Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/argv_split.c | 83 +++++++++++++++++++-------------------------- 1 file changed, 36 insertions(+), 47 deletions(-) diff -puN lib/argv_split.c~argv_split-teach-it-to-handle-mutable-strings lib/argv_split.c --- a/lib/argv_split.c~argv_split-teach-it-to-handle-mutable-strings +++ a/lib/argv_split.c @@ -8,23 +8,17 @@ #include <linux/slab.h> #include <linux/export.h> -static const char *skip_arg(const char *cp) -{ - while (*cp && !isspace(*cp)) - cp++; - - return cp; -} - static int count_argc(const char *str) { int count = 0; + bool was_space; - while (*str) { - str = skip_spaces(str); - if (*str) { + for (was_space = true; *str; str++) { + if (isspace(*str)) { + was_space = true; + } else if (was_space) { + was_space = false; count++; - str = skip_arg(str); } } @@ -39,10 +33,8 @@ static int count_argc(const char *str) */ void argv_free(char **argv) { - char **p; - for (p = argv; *p; p++) - kfree(*p); - + argv--; + kfree(argv[0]); kfree(argv); } EXPORT_SYMBOL(argv_free); @@ -62,40 +54,37 @@ EXPORT_SYMBOL(argv_free); */ char **argv_split(gfp_t gfp, const char *str, int *argcp) { - int argc = count_argc(str); - char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp); - char **argvp; - - if (argv == NULL) - goto out; - - if (argcp) - *argcp = argc; - - argvp = argv; - - while (*str) { - str = skip_spaces(str); - - if (*str) { - const char *p = str; - char *t; - - str = skip_arg(str); + char *argv_str; + bool was_space; + char **argv, **argv_ret; + int argc; + + argv_str = kstrndup(str, KMALLOC_MAX_SIZE, gfp); + if (!argv_str) + return NULL; + + argc = count_argc(argv_str); + argv = kmalloc(sizeof(*argv) * (argc + 2), gfp); + if (!argv) { + kfree(argv_str); + return NULL; + } - t = kstrndup(p, str-p, gfp); - if (t == NULL) - goto fail; - *argvp++ = t; + *argv = argv_str; + argv_ret = ++argv; + for (was_space = true; *argv_str; argv_str++) { + if (isspace(*argv_str)) { + was_space = true; + *argv_str = 0; + } else if (was_space) { + was_space = false; + *argv++ = argv_str; } } - *argvp = NULL; - - out: - return argv; + *argv = NULL; - fail: - argv_free(argv); - return NULL; + if (argcp) + *argcp = argc; + return argv_ret; } EXPORT_SYMBOL(argv_split); _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are poweroff-change-orderly_poweroff-to-use-schedule_work.patch thinkpad-acpi-kill-hotkey_thread_mutex.patch kthread-introduce-to_live_kthread.patch kthread-kill-task_get_live_kthread.patch posix_cpu_timer-consolidate-expiry-time-type.patch posix_cpu_timers-consolidate-timer-list-cleanups.patch posix_cpu_timers-consolidate-expired-timers-check.patch lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch argv_split-teach-it-to-handle-mutable-strings.patch argv_split-teach-it-to-handle-mutable-strings-fix.patch epoll-use-rcu-to-protect-wakeup_source-in-epitem.patch ptrace-add-ability-to-retrieve-signals-without-removing-from-a-queue-v4.patch selftest-add-a-test-case-for-ptrace_peeksiginfo.patch usermodehelper-export-_exec-and-_setup-functions.patch usermodehelper-export-_exec-and-_setup-functions-fix.patch kmod-split-call-to-call_usermodehelper_fns.patch keys-split-call-to-call_usermodehelper_fns.patch coredump-remove-trailling-whitespaces.patch split-remaining-calls-to-call_usermodehelper_fns.patch kmod-remove-call_usermodehelper_fns.patch coredump-only-sigkill-should-interrupt-the-coredumping-task.patch coredump-ensure-that-sigkill-always-kills-the-dumping-thread.patch coredump-sanitize-the-setting-of-signal-group_exit_code.patch coredump-introduce-dump_interrupted.patch coredump-factor-out-the-setting-of-pf_dumpcore.patch coredump-change-wait_for_dump_helpers-to-use-wait_event_interruptible.patch set_task_comm-kill-the-pointless-memset-wmb.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html