From: Marijn Suijten <marijn.suijten@somainline.org>
To: phone-devel@vger.kernel.org
Cc: ~postmarketos/upstreaming@lists.sr.ht,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@somainline.org>,
Konrad Dybcio <konrad.dybcio@somainline.org>,
Martin Botka <martin.botka@somainline.org>,
Jami Kettunen <jami.kettunen@somainline.org>,
Pavel Dubrova <pashadubrova@gmail.com>,
Marijn Suijten <marijn.suijten@somainline.org>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Lee Jones <lee.jones@linaro.org>,
Daniel Thompson <daniel.thompson@linaro.org>,
Jingoo Han <jingoohan1@gmail.com>,
Courtney Cavin <courtney.cavin@sonymobile.com>,
Bryan Wu <cooloney@gmail.com>,
linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 04/13] backlight: qcom-wled: Fix off-by-one maximum with default num_strings
Date: Thu, 7 Oct 2021 23:33:51 +0200 [thread overview]
Message-ID: <20211007213400.258371-5-marijn.suijten@somainline.org> (raw)
In-Reply-To: <20211007213400.258371-1-marijn.suijten@somainline.org>
When not specifying num-strings in the DT the default is used, but +1 is
added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead
of 3 and 4 respectively, causing out-of-bounds reads and register
read/writes. This +1 exists for a deficiency in the DT parsing code,
and is simply omitted entirely - solving this oob issue - by parsing the
property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when
qcom,enabled-strings is provided in the DT. Note that num-strings is
parsed after enabled-strings to give it final sign-off over the length,
which DT currently utilizes to get around an incorrect fixed read of
four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-By: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
---
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------
1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index 977cd75827d7..c5232478a343 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -1253,21 +1253,6 @@ static const struct wled_var_cfg wled5_ovp_cfg = {
.size = 16,
};
-static u32 wled3_num_strings_values_fn(u32 idx)
-{
- return idx + 1;
-}
-
-static const struct wled_var_cfg wled3_num_strings_cfg = {
- .fn = wled3_num_strings_values_fn,
- .size = 3,
-};
-
-static const struct wled_var_cfg wled4_num_strings_cfg = {
- .fn = wled3_num_strings_values_fn,
- .size = 4,
-};
-
static u32 wled3_switch_freq_values_fn(u32 idx)
{
return 19200 / (2 * (1 + idx));
@@ -1341,11 +1326,6 @@ static int wled_configure(struct wled *wled)
.val_ptr = &cfg->switch_freq,
.cfg = &wled3_switch_freq_cfg,
},
- {
- .name = "qcom,num-strings",
- .val_ptr = &cfg->num_strings,
- .cfg = &wled3_num_strings_cfg,
- },
};
const struct wled_u32_opts wled4_opts[] = {
@@ -1369,11 +1349,6 @@ static int wled_configure(struct wled *wled)
.val_ptr = &cfg->switch_freq,
.cfg = &wled3_switch_freq_cfg,
},
- {
- .name = "qcom,num-strings",
- .val_ptr = &cfg->num_strings,
- .cfg = &wled4_num_strings_cfg,
- },
};
const struct wled_u32_opts wled5_opts[] = {
@@ -1397,11 +1372,6 @@ static int wled_configure(struct wled *wled)
.val_ptr = &cfg->switch_freq,
.cfg = &wled3_switch_freq_cfg,
},
- {
- .name = "qcom,num-strings",
- .val_ptr = &cfg->num_strings,
- .cfg = &wled4_num_strings_cfg,
- },
{
.name = "qcom,modulator-sel",
.val_ptr = &cfg->mod_sel,
@@ -1520,8 +1490,6 @@ static int wled_configure(struct wled *wled)
*bool_opts[i].val_ptr = true;
}
- cfg->num_strings = cfg->num_strings + 1;
-
string_len = of_property_count_elems_of_size(dev->of_node,
"qcom,enabled-strings",
sizeof(u32));
@@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled)
}
}
+ rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
+ if (!rc) {
+ if (val < 1 || val > wled->max_string_count) {
+ dev_err(dev, "qcom,num-strings must be between 1 and %d\n",
+ wled->max_string_count);
+ return -EINVAL;
+ }
+
+ if (string_len > 0) {
+ dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");
+ if (val > string_len) {
+ dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");
+ return -EINVAL;
+ }
+ }
+
+ cfg->num_strings = val;
+ }
+
return 0;
}
--
2.33.0
next prev parent reply other threads:[~2021-10-07 21:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-07 21:33 [PATCH v2 00/13] backlight: qcom-wled: fix and solidify handling of enabled-strings Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 01/13] backlight: qcom-wled: Validate enabled string indices in DT Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 02/13] backlight: qcom-wled: Pass number of elements to read to read_u32_array Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 03/13] backlight: qcom-wled: Use cpu_to_le16 macro to perform conversion Marijn Suijten
2021-10-07 21:33 ` Marijn Suijten [this message]
2021-10-07 21:33 ` [PATCH v2 05/13] backlight: qcom-wled: Override default length with qcom,enabled-strings Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 06/13] backlight: qcom-wled: Remove unnecessary 4th default string in WLED3 Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 07/13] backlight: qcom-wled: Provide enabled_strings default for WLED 4 and 5 Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 08/13] backlight: qcom-wled: Remove unnecessary double whitespace Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 09/13] backlight: qcom-wled: Respect enabled-strings in set_brightness Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 10/13] arm64: dts: qcom: pmi8994: Fix "eternal"->"external" typo in WLED node Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 11/13] arm64: dts: qcom: pmi8994: Remove hardcoded linear WLED enabled-strings Marijn Suijten
2021-10-07 21:33 ` [PATCH v2 12/13] arm64: dts: qcom: Move WLED num-strings from pmi8994 to sony-xperia-tone Marijn Suijten
2021-10-07 21:34 ` [PATCH v2 13/13] arm64: dt: qcom: pm660l: Remove board-specific WLED configuration Marijn Suijten
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