From: Chuck Lever III <chuck.lever@oracle.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
David Wysochanski <dwysocha@redhat.com>,
Bruce Fields <bfields@fieldses.org>
Subject: Re: [PATCH v2 01/25] NFSD: Fix TP_printk() format specifier in trace_nfsd_dirent()
Date: Thu, 13 May 2021 20:01:00 +0000 [thread overview]
Message-ID: <5BC8482E-1902-432A-B162-774A96E4C2B7@oracle.com> (raw)
In-Reply-To: <20210513151721.02a7fdd1@gandalf.local.home>
> On May 13, 2021, at 3:17 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 13 May 2021 19:08:13 +0000
> Chuck Lever III <chuck.lever@oracle.com> wrote:
>
>> The tracepoints that currently use '%.*s' no longer work when
>> using "trace-cmd start/stop/show". They were working before
>> 9a6944fee68e, so I consider this a regression. I plan to
>> submit patches to address this for 5.13-rc. I guess they will
>> have to go without the use of the new _len macros for now,
>> and you can push the macros in v5.14.
>
> That's a separate bug. I'm currently running this patch through my tests,
> and will push to Linus when it completes. Feel free to test this one too.
Confirmed that applying the below patch addresses the regression.
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Thanks for your quick response!
> -- Steve
>
> From eb01f5353bdaa59600b29d864819056a0e3de24d Mon Sep 17 00:00:00 2001
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> Date: Thu, 13 May 2021 12:23:24 -0400
> Subject: [PATCH] tracing: Handle %.*s in trace_check_vprintf()
>
> If a trace event uses the %*.s notation, the trace_check_vprintf() will
> fail and will warn about a bad processing of strings, because it does not
> take into account the length field when processing the star (*) part.
> Have it handle this case as well.
>
> Link: https://lore.kernel.org/linux-nfs/238C0E2D-C2A4-4578-ADD2-C565B3B99842@oracle.com/
>
> Reported-by: Chuck Lever III <chuck.lever@oracle.com>
> Fixes: 9a6944fee68e2 ("tracing: Add a verifier to check string pointers for trace events")
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/trace/trace.c | 31 +++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 560e4c8d3825..a21ef9cd2aae 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -3704,6 +3704,9 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
> goto print;
>
> while (*p) {
> + bool star = false;
> + int len = 0;
> +
> j = 0;
>
> /* We only care about %s and variants */
> @@ -3725,13 +3728,17 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
> /* Need to test cases like %08.*s */
> for (j = 1; p[i+j]; j++) {
> if (isdigit(p[i+j]) ||
> - p[i+j] == '*' ||
> p[i+j] == '.')
> continue;
> + if (p[i+j] == '*') {
> + star = true;
> + continue;
> + }
> break;
> }
> if (p[i+j] == 's')
> break;
> + star = false;
> }
> j = 0;
> }
> @@ -3744,6 +3751,9 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
> iter->fmt[i] = '\0';
> trace_seq_vprintf(&iter->seq, iter->fmt, ap);
>
> + if (star)
> + len = va_arg(ap, int);
> +
> /* The ap now points to the string data of the %s */
> str = va_arg(ap, const char *);
>
> @@ -3762,8 +3772,18 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
> int ret;
>
> /* Try to safely read the string */
> - ret = strncpy_from_kernel_nofault(iter->fmt, str,
> - iter->fmt_size);
> + if (star) {
> + if (len + 1 > iter->fmt_size)
> + len = iter->fmt_size - 1;
> + if (len < 0)
> + len = 0;
> + ret = copy_from_kernel_nofault(iter->fmt, str, len);
> + iter->fmt[len] = 0;
> + star = false;
> + } else {
> + ret = strncpy_from_kernel_nofault(iter->fmt, str,
> + iter->fmt_size);
> + }
> if (ret < 0)
> trace_seq_printf(&iter->seq, "(0x%px)", str);
> else
> @@ -3775,7 +3795,10 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
> strncpy(iter->fmt, p + i, j + 1);
> iter->fmt[j+1] = '\0';
> }
> - trace_seq_printf(&iter->seq, iter->fmt, str);
> + if (star)
> + trace_seq_printf(&iter->seq, iter->fmt, len, str);
> + else
> + trace_seq_printf(&iter->seq, iter->fmt, str);
>
> p += i + j + 1;
> }
> --
> 2.29.2
>
--
Chuck Lever
next prev parent reply other threads:[~2021-05-13 20:01 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 15:34 [PATCH v2 00/25] NFSD callback and lease management observability Chuck Lever
2021-05-12 15:35 ` [PATCH v2 01/25] NFSD: Fix TP_printk() format specifier in trace_nfsd_dirent() Chuck Lever
2021-05-12 16:26 ` Steven Rostedt
2021-05-12 16:52 ` Chuck Lever III
2021-05-13 14:50 ` Steven Rostedt
2021-05-13 14:53 ` Chuck Lever III
2021-05-13 15:02 ` Steven Rostedt
2021-05-13 15:10 ` Chuck Lever III
2021-05-13 18:43 ` Chuck Lever III
2021-05-13 19:00 ` Steven Rostedt
2021-05-13 19:08 ` Chuck Lever III
2021-05-13 19:17 ` Steven Rostedt
2021-05-13 20:01 ` Chuck Lever III [this message]
2021-07-12 15:18 ` Chuck Lever III
2021-07-12 17:09 ` Steven Rostedt
2021-05-12 16:53 ` Steven Rostedt
2021-05-12 15:35 ` [PATCH v2 02/25] NFSD: Fix TP_printk() format specifier in nfsd_clid_class Chuck Lever
2021-05-12 15:35 ` [PATCH v2 03/25] NFSD: Add nfsd_clid_cred_mismatch tracepoint Chuck Lever
2021-05-12 15:35 ` [PATCH v2 04/25] NFSD: Add nfsd_clid_verf_mismatch tracepoint Chuck Lever
2021-05-12 15:35 ` [PATCH v2 05/25] NFSD: Remove trace_nfsd_clid_inuse_err Chuck Lever
2021-05-12 15:35 ` [PATCH v2 06/25] NFSD: Add nfsd_clid_confirmed tracepoint Chuck Lever
2021-05-12 15:35 ` [PATCH v2 07/25] NFSD: Add nfsd_clid_reclaim_complete tracepoint Chuck Lever
2021-05-12 15:35 ` [PATCH v2 08/25] NFSD: Add nfsd_clid_destroyed tracepoint Chuck Lever
2021-05-12 15:35 ` [PATCH v2 09/25] NFSD: Add a couple more nfsd_clid_expired call sites Chuck Lever
2021-05-13 16:42 ` David Wysochanski
2021-05-13 17:05 ` Chuck Lever III
2021-05-12 15:36 ` [PATCH v2 10/25] NFSD: Add an RPC authflavor tracepoint display helper Chuck Lever
2021-05-12 15:36 ` [PATCH v2 11/25] NFSD: Add tracepoints for SETCLIENTID edge cases Chuck Lever
2021-05-12 15:36 ` [PATCH v2 12/25] NFSD: Add tracepoints for EXCHANGEID " Chuck Lever
2021-05-12 15:36 ` [PATCH v2 13/25] NFSD: Constify @fh argument of knfsd_fh_hash() Chuck Lever
2021-05-12 15:36 ` [PATCH v2 14/25] NFSD: Capture every CB state transition Chuck Lever
2021-05-12 15:36 ` [PATCH v2 15/25] NFSD: Drop TRACE_DEFINE_ENUM for NFSD4_CB_<state> macros Chuck Lever
2021-05-12 15:36 ` [PATCH v2 16/25] NFSD: Add cb_lost tracepoint Chuck Lever
2021-05-12 15:36 ` [PATCH v2 17/25] NFSD: Adjust cb_shutdown tracepoint Chuck Lever
2021-05-12 15:36 ` [PATCH v2 18/25] NFSD: Remove spurious cb_setup_err tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 19/25] NFSD: Enhance the nfsd_cb_setup tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 20/25] NFSD: Add an nfsd_cb_lm_notify tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 21/25] NFSD: Add an nfsd_cb_offload tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 22/25] NFSD: Replace the nfsd_deleg_break tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 23/25] NFSD: Add an nfsd_cb_probe tracepoint Chuck Lever
2021-05-12 15:37 ` [PATCH v2 24/25] NFSD: Remove the nfsd_cb_work and nfsd_cb_done tracepoints Chuck Lever
2021-05-12 15:37 ` [PATCH v2 25/25] NFSD: Update nfsd_cb_args tracepoint Chuck Lever
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