| Message ID | 20220627161642.1.Ie7b480cd99e2c13319220cbc108caf2bcd41286b@changeid (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | soc: qcom: cmd-db: replace strscpy_pad() with strncpy() | expand |
On Mon, Jun 27, 2022 at 04:17:00PM -0700, Douglas Anderson wrote: > Commit ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with > strscpy_pad()") breaks booting on my sc7280-herobrine-herobrine > device. From printouts I see that at bootup the function is called > with an id of "lnbclka2" which is 8 bytes big. > > Previously all 8 bytes of this string were copied to the > destination. Now only 7 bytes will be copied since strscpy_pad() saves > a byte for '\0' termination. > > We don't need the '\0' termination in the destination. Let's go back > to strncpy(). According to the warning: > If a caller is using non-NUL-terminated strings, strncpy() can still > be used, but destinations should be marked with the __nonstring > attribute to avoid future compiler warnings. > ...so we'll do that. > > Fixes: ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with strscpy_pad()") > Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Quoting Douglas Anderson (2022-06-27 16:17:00) > Commit ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with > strscpy_pad()") breaks booting on my sc7280-herobrine-herobrine > device. From printouts I see that at bootup the function is called > with an id of "lnbclka2" which is 8 bytes big. > > Previously all 8 bytes of this string were copied to the > destination. Now only 7 bytes will be copied since strscpy_pad() saves > a byte for '\0' termination. > > We don't need the '\0' termination in the destination. Let's go back > to strncpy(). According to the warning: > If a caller is using non-NUL-terminated strings, strncpy() can still > be used, but destinations should be marked with the __nonstring > attribute to avoid future compiler warnings. > ...so we'll do that. > > Fixes: ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with strscpy_pad()") > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > drivers/soc/qcom/cmd-db.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c > index c5137c25d819..0aafe90277bc 100644 > --- a/drivers/soc/qcom/cmd-db.c > +++ b/drivers/soc/qcom/cmd-db.c > @@ -141,14 +141,14 @@ static int cmd_db_get_header(const char *id, const struct entry_header **eh, > const struct rsc_hdr *rsc_hdr; > const struct entry_header *ent; > int ret, i, j; > - u8 query[8]; > + u8 query[8] __nonstring; Since you're already here, can you change 8 to be sizeof(ent->id)? That would directly tie the two lengths together so that one can't change and then the carefully crafted strncpy() fails again. > > ret = cmd_db_ready(); > if (ret) > return ret; > > /* Pad out query string to same length as in DB */ > - strscpy_pad(query, id, sizeof(query)); > + strncpy(query, id, sizeof(query));
diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c index c5137c25d819..0aafe90277bc 100644 --- a/drivers/soc/qcom/cmd-db.c +++ b/drivers/soc/qcom/cmd-db.c @@ -141,14 +141,14 @@ static int cmd_db_get_header(const char *id, const struct entry_header **eh, const struct rsc_hdr *rsc_hdr; const struct entry_header *ent; int ret, i, j; - u8 query[8]; + u8 query[8] __nonstring; ret = cmd_db_ready(); if (ret) return ret; /* Pad out query string to same length as in DB */ - strscpy_pad(query, id, sizeof(query)); + strncpy(query, id, sizeof(query)); for (i = 0; i < MAX_SLV_ID; i++) { rsc_hdr = &cmd_db_header->header[i];
Commit ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with strscpy_pad()") breaks booting on my sc7280-herobrine-herobrine device. From printouts I see that at bootup the function is called with an id of "lnbclka2" which is 8 bytes big. Previously all 8 bytes of this string were copied to the destination. Now only 7 bytes will be copied since strscpy_pad() saves a byte for '\0' termination. We don't need the '\0' termination in the destination. Let's go back to strncpy(). According to the warning: If a caller is using non-NUL-terminated strings, strncpy() can still be used, but destinations should be marked with the __nonstring attribute to avoid future compiler warnings. ...so we'll do that. Fixes: ac0126a01735 ("soc: qcom: cmd-db: replace strncpy() with strscpy_pad()") Signed-off-by: Douglas Anderson <dianders@chromium.org> --- drivers/soc/qcom/cmd-db.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)