| Message ID | 20210222151231.22572-12-romain.perier@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Manual replacement of all strlcpy in favor of strscpy | expand |
On 2/22/21 7:12 AM, Romain Perier wrote: > The strlcpy() reads the entire source buffer first, it is dangerous if > the source buffer lenght is unbounded or possibility non NULL-terminated. length > It can lead to linear read overflows, crashes, etc... > Not here. This description is misleading. > As recommended in the deprecated interfaces [1], it should be replaced > by strscpy. > > This commit replaces all calls to strlcpy that handle the return values > by the corresponding strscpy calls with new handling of the return > values (as it is quite different between the two functions). > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > > Signed-off-by: Romain Perier <romain.perier@gmail.com> This patch just adds pain to injury, as the source 'buffers' are all fixed strings and their length will never exceed the maximum buffer length. I really don't see the point of using strscpy() in this situation. > --- > drivers/hwmon/pmbus/max20730.c | 66 +++++++++++++++++++++-------------------- This patch only modifies a single driver and should be tagged as such. > 1 file changed, 35 insertions(+), 31 deletions(-) > > diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c > index 9dd3dd79bc18..a384b57b7327 100644 > --- a/drivers/hwmon/pmbus/max20730.c > +++ b/drivers/hwmon/pmbus/max20730.c > @@ -107,7 +107,8 @@ struct max20730_debugfs_data { > static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > size_t count, loff_t *ppos) > { > - int ret, len; > + int ret; > + ssize_t len; > int *idxp = file->private_data; > int idx = *idxp; > struct max20730_debugfs_data *psu = to_psu(idxp, idx); > @@ -148,13 +149,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > >> MAX20730_MFR_DEVSET1_TSTAT_BIT_POS; > > if (val == 0) > - len = strlcpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "125\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "125\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "32\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "32\n", DEBUG_FS_DATA_MAX); > break; > case MAX20730_DEBUGFS_INTERNAL_GAIN: > val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_RGAIN_MASK) > @@ -163,35 +164,35 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > if (data->id == max20734) { > /* AN6209 */ > if (val == 0) > - len = strlcpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX); > } else if (data->id == max20730 || data->id == max20710) { > /* AN6042 or AN6140 */ > if (val == 0) > - len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX); > } else if (data->id == max20743) { > /* AN6042 */ > if (val == 0) > - len = strlcpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); > } else { > - len = strlcpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX); > } > break; > case MAX20730_DEBUGFS_BOOT_VOLTAGE: > @@ -199,26 +200,26 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > >> MAX20730_MFR_DEVSET1_VBOOT_BIT_POS; > > if (val == 0) > - len = strlcpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > break; > case MAX20730_DEBUGFS_OUT_V_RAMP_RATE: > val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_VRATE) > >> MAX20730_MFR_DEVSET2_VRATE_BIT_POS; > > if (val == 0) > - len = strlcpy(tbuf, "4\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "4\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "2\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "2\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "1\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > break; > case MAX20730_DEBUGFS_OC_PROTECT_MODE: > ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK) > @@ -230,13 +231,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > >> MAX20730_MFR_DEVSET2_SS_BIT_POS; > > if (val == 0) > - len = strlcpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX); > else if (val == 1) > - len = strlcpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX); > else if (val == 2) > - len = strlcpy(tbuf, "3\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "3\n", DEBUG_FS_DATA_MAX); > else > - len = strlcpy(tbuf, "6\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "6\n", DEBUG_FS_DATA_MAX); > break; > case MAX20730_DEBUGFS_IMAX: > ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK) > @@ -287,9 +288,12 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > "%d.%d\n", ret / 10000, ret % 10000); > break; > default: > - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); > } > > + if (len == -E2BIG) > + return -E2BIG; > + > return simple_read_from_buffer(buf, count, ppos, tbuf, len); > } > >
Le lun. 22 févr. 2021 à 16:46, Guenter Roeck <linux@roeck-us.net> a écrit : > On 2/22/21 7:12 AM, Romain Perier wrote: > > The strlcpy() reads the entire source buffer first, it is dangerous if > > the source buffer lenght is unbounded or possibility non NULL-terminated. > > length > > > It can lead to linear read overflows, crashes, etc... > > > Not here. This description is misleading. > > > As recommended in the deprecated interfaces [1], it should be replaced > > by strscpy. > > > > This commit replaces all calls to strlcpy that handle the return values > > by the corresponding strscpy calls with new handling of the return > > values (as it is quite different between the two functions). > > > > [1] > https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > > > > Signed-off-by: Romain Perier <romain.perier@gmail.com> > > This patch just adds pain to injury, as the source 'buffers' are all fixed > strings and their length will never exceed the maximum buffer length. > I really don't see the point of using strscpy() in this situation. > > Hi, No, no insult or offense at all here (sorry if you understood like this, it is not my intention ^^), it is just a general description of what the usage of strlcpy might cause (the description is not specific to your code). The initial idea was to globally replace all occurrences of the old by the new functions (the old being deprecated for a reason), however, if some maintainers disagree or don't think that their drivers are affected, no problem we can exclude these from the patches series. Romain
On Mon, 2021-02-22 at 07:46 -0800, Guenter Roeck wrote: > On 2/22/21 7:12 AM, Romain Perier wrote: > > The strlcpy() reads the entire source buffer first, it is dangerous if > > the source buffer lenght is unbounded or possibility non NULL-terminated. > > length > > > It can lead to linear read overflows, crashes, etc... > > > Not here. This description is misleading. > > > As recommended in the deprecated interfaces [1], it should be replaced > > by strscpy. > > > > This commit replaces all calls to strlcpy that handle the return values > > by the corresponding strscpy calls with new handling of the return > > values (as it is quite different between the two functions). > > > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy > > > > Signed-off-by: Romain Perier <romain.perier@gmail.com> > > This patch just adds pain to injury, as the source 'buffers' are all fixed > strings and their length will never exceed the maximum buffer length. > I really don't see the point of using strscpy() in this situation. Might as well just use strcpy (I'd still prefer stracpy) https://lore.kernel.org/lkml/24bb53c57767c1c2a8f266c305a670f7@sk2.org/T/
diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c index 9dd3dd79bc18..a384b57b7327 100644 --- a/drivers/hwmon/pmbus/max20730.c +++ b/drivers/hwmon/pmbus/max20730.c @@ -107,7 +107,8 @@ struct max20730_debugfs_data { static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { - int ret, len; + int ret; + ssize_t len; int *idxp = file->private_data; int idx = *idxp; struct max20730_debugfs_data *psu = to_psu(idxp, idx); @@ -148,13 +149,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, >> MAX20730_MFR_DEVSET1_TSTAT_BIT_POS; if (val == 0) - len = strlcpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "2000\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "125\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "125\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "62.5\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "32\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "32\n", DEBUG_FS_DATA_MAX); break; case MAX20730_DEBUGFS_INTERNAL_GAIN: val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_RGAIN_MASK) @@ -163,35 +164,35 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, if (data->id == max20734) { /* AN6209 */ if (val == 0) - len = strlcpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.8\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "3.2\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1.6\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "6.4\n", DEBUG_FS_DATA_MAX); } else if (data->id == max20730 || data->id == max20710) { /* AN6042 or AN6140 */ if (val == 0) - len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "7.2\n", DEBUG_FS_DATA_MAX); } else if (data->id == max20743) { /* AN6042 */ if (val == 0) - len = strlcpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.45\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1.8\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.9\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "3.6\n", DEBUG_FS_DATA_MAX); } else { - len = strlcpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "Not supported\n", DEBUG_FS_DATA_MAX); } break; case MAX20730_DEBUGFS_BOOT_VOLTAGE: @@ -199,26 +200,26 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, >> MAX20730_MFR_DEVSET1_VBOOT_BIT_POS; if (val == 0) - len = strlcpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.6484\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.8984\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1.0\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); break; case MAX20730_DEBUGFS_OUT_V_RAMP_RATE: val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_VRATE) >> MAX20730_MFR_DEVSET2_VRATE_BIT_POS; if (val == 0) - len = strlcpy(tbuf, "4\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "4\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "2\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "2\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "1\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); break; case MAX20730_DEBUGFS_OC_PROTECT_MODE: ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK) @@ -230,13 +231,13 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, >> MAX20730_MFR_DEVSET2_SS_BIT_POS; if (val == 0) - len = strlcpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "0.75\n", DEBUG_FS_DATA_MAX); else if (val == 1) - len = strlcpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "1.5\n", DEBUG_FS_DATA_MAX); else if (val == 2) - len = strlcpy(tbuf, "3\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "3\n", DEBUG_FS_DATA_MAX); else - len = strlcpy(tbuf, "6\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "6\n", DEBUG_FS_DATA_MAX); break; case MAX20730_DEBUGFS_IMAX: ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK) @@ -287,9 +288,12 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, "%d.%d\n", ret / 10000, ret % 10000); break; default: - len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); + len = strscpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX); } + if (len == -E2BIG) + return -E2BIG; + return simple_read_from_buffer(buf, count, ppos, tbuf, len); }
The strlcpy() reads the entire source buffer first, it is dangerous if the source buffer lenght is unbounded or possibility non NULL-terminated. It can lead to linear read overflows, crashes, etc... As recommended in the deprecated interfaces [1], it should be replaced by strscpy. This commit replaces all calls to strlcpy that handle the return values by the corresponding strscpy calls with new handling of the return values (as it is quite different between the two functions). [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy Signed-off-by: Romain Perier <romain.perier@gmail.com> --- drivers/hwmon/pmbus/max20730.c | 66 +++++++++++++++++++++-------------------- 1 file changed, 35 insertions(+), 31 deletions(-)