Re: [PATCH v2 2/2] trace: kdb: Replace simple_strtoul with kstrtoul in kdb_ftdump

From: Google
Date: Wed Oct 23 2024 - 04:49:55 EST


On Mon, 21 Oct 2024 21:17:24 +0000
Nir Lichtman <nir@xxxxxxxxxxxx> wrote:

> The function simple_strtoul performs no error checking in scenarios
> where the input value overflows the intended output variable.
> This results in this function successfully returning, even when the
> output does not match the input string (aka the function returns
> successfully even when the result is wrong).
>
> Or as it was mentioned [1], "...simple_strtol(), simple_strtoll(),
> simple_strtoul(), and simple_strtoull() functions explicitly ignore
> overflows, which may lead to unexpected results in callers."
> Hence, the use of those functions is discouraged.
>
> This patch replaces all uses of the simple_strtoul with the safer
> alternatives kstrtoint and kstrtol.
>
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull
>

Looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thank you,

> Signed-off-by: Yuran Pereira <yuran.pereira@xxxxxxxxxxx>
> Signed-off-by: Nir Lichtman <nir@xxxxxxxxxxxx>
> ---
> kernel/trace/trace_kdb.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
> index 59857a1ee44c..eadda6e05526 100644
> --- a/kernel/trace/trace_kdb.c
> +++ b/kernel/trace/trace_kdb.c
> @@ -96,23 +96,20 @@ static int kdb_ftdump(int argc, const char **argv)
> {
> int skip_entries = 0;
> long cpu_file;
> - char *cp;
> + int err;
> int cnt;
> int cpu;
>
> if (argc > 2)
> return KDB_ARGCOUNT;
>
> - if (argc) {
> - skip_entries = simple_strtol(argv[1], &cp, 0);
> - if (*cp)
> - skip_entries = 0;
> - }
> + if (argc && kstrtoint(argv[1], 0, &skip_entries))
> + return KDB_BADINT;
>
> if (argc == 2) {
> - cpu_file = simple_strtol(argv[2], &cp, 0);
> - if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
> - !cpu_online(cpu_file))
> + err = kstrtol(argv[2], 0, &cpu_file);
> + if (err || cpu_file >= NR_CPUS || cpu_file < 0 ||
> + !cpu_online(cpu_file))
> return KDB_BADINT;
> } else {
> cpu_file = RING_BUFFER_ALL_CPUS;
> --
> 2.39.2


--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>