From: Prarit Bhargava <prarit@redhat.com>
To: Daniel Thompson <daniel.thompson@linaro.org>,
linux-kernel@vger.kernel.org
Cc: Jonathan Toppins <jtoppins@redhat.com>,
Jason Wessel <jason.wessel@windriver.com>,
kgdb-bugreport@lists.sourceforge.net
Subject: Re: [PATCH v2] kdb: Use strscpy with destination buffer size
Date: Thu, 4 Oct 2018 08:25:30 -0400 [thread overview]
Message-ID: <78793735-c2ce-62f6-d745-5fc06a17beb1@redhat.com> (raw)
In-Reply-To: <9192af58-7966-c023-8b19-5b291839a228@linaro.org>
On 10/02/2018 11:53 AM, Daniel Thompson wrote:
> On 20/09/2018 13:59, Prarit Bhargava wrote:
>> gcc 8.1.0 warns with:
>>
>> kernel/debug/kdb/kdb_support.c: In function ‘kallsyms_symbol_next’:
>> kernel/debug/kdb/kdb_support.c:239:4: warning: ‘strncpy’ specified bound
>> depends on the length of the source argument [-Wstringop-overflow=]
>> strncpy(prefix_name, name, strlen(name)+1);
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> kernel/debug/kdb/kdb_support.c:239:31: note: length computed here
>>
>> Use strscpy() with the destination buffer size, and use ellipses when
>> displaying truncated symbols.
>>
>> v2: Use strscpy()
>>
>> Signed-off-by: Prarit Bhargava <prarit@redhat.com>
>> Cc: Jonathan Toppins <jtoppins@redhat.com>
>> Cc: Jason Wessel <jason.wessel@windriver.com>
>> Cc: Daniel Thompson <daniel.thompson@linaro.org>
>> Cc: kgdb-bugreport@lists.sourceforge.net
>> ---
>> kernel/debug/kdb/kdb_io.c | 15 +++++++++------
>> kernel/debug/kdb/kdb_private.h | 2 +-
>> kernel/debug/kdb/kdb_support.c | 10 +++++-----
>> 3 files changed, 15 insertions(+), 12 deletions(-)
>>
>> diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
>> index ed5d34925ad0..6a4b41484afe 100644
>> --- a/kernel/debug/kdb/kdb_io.c
>> +++ b/kernel/debug/kdb/kdb_io.c
>> @@ -216,7 +216,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
>> int count;
>> int i;
>> int diag, dtab_count;
>> - int key;
>> + int key, buf_size, ret;
>> diag = kdbgetintenv("DTABCOUNT", &dtab_count);
>> @@ -336,9 +336,8 @@ static char *kdb_read(char *buffer, size_t bufsize)
>> else
>> p_tmp = tmpbuffer;
>> len = strlen(p_tmp);
>> - count = kallsyms_symbol_complete(p_tmp,
>> - sizeof(tmpbuffer) -
>> - (p_tmp - tmpbuffer));
>> + buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
>> + count = kallsyms_symbol_complete(p_tmp, buf_size);
>> if (tab == 2 && count > 0) {
>> kdb_printf("\n%d symbols are found.", count);
>> if (count > dtab_count) {
>> @@ -350,9 +349,13 @@ static char *kdb_read(char *buffer, size_t bufsize)
>> }
>> kdb_printf("\n");
>> for (i = 0; i < count; i++) {
>> - if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
>> + ret = kallsyms_symbol_next(p_tmp, i, buf_size);
>> + if (WARN_ON(!ret))
>> break;
> I'm getting confused by having two different branches on ret.
>
> Don't get a WARN_ON() when ret == -E2BIG?
>
>
Should we WARN on a really long symbol? I don't think we should as we're
handling that by truncating the output and adding ellipses below.
P.
> Daniel.
>
>
>> - kdb_printf("%s ", p_tmp);
>> + if (ret != -E2BIG)
>> + kdb_printf("%s ", p_tmp);
>> + else
>> + kdb_printf("%s... ", p_tmp);
>> *(p_tmp + len) = '\0';
>> }
>> if (i >= dtab_count)
next prev parent reply other threads:[~2018-10-04 12:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 12:59 [PATCH v2] kdb: Use strscpy with destination buffer size Prarit Bhargava
2018-10-02 15:53 ` Daniel Thompson
2018-10-04 12:25 ` Prarit Bhargava [this message]
2018-10-04 12:45 ` Daniel Thompson
2018-10-18 12:15 ` Prarit Bhargava
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