| Message ID | 20231007170448.505487-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] modpost: fix tee MODULE_DEVICE_TABLE built on big endian host | expand |
Hi Masahiro, On Sat, 7 Oct 2023 at 22:34, Masahiro Yamada <masahiroy@kernel.org> wrote: > > When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different > endianness from the target architecture, it results in an incorrect > MODULE_ALIAS(). > > For example, see a case where drivers/char/hw_random/optee-rng.c > is built as a module. > > If you build it on a little endian host, you will get the correct > MODULE_ALIAS: > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*"); > > However, if you build it on a big endian host, you will get a wrong > MODULE_ALIAS: > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*"); > > This issue has been unnoticed because the ARM kernel is most likely built > on a little endian host (cross-build on x86 or native-build on ARM). > > The uuid field must not be reversed because uuid_t is an array of __u8. > To me it wasn't obvious that DEF_FIELD() has certain endianness limitations. > Fixes: 0fc1db9d1059 ("tee: add bus driver framework for TEE based devices") > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > scripts/mod/file2alias.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > index 7056751c29b1..70bf6a2f585c 100644 > --- a/scripts/mod/file2alias.c > +++ b/scripts/mod/file2alias.c > @@ -1348,13 +1348,13 @@ static int do_typec_entry(const char *filename, void *symval, char *alias) > /* Looks like: tee:uuid */ > static int do_tee_entry(const char *filename, void *symval, char *alias) > { > - DEF_FIELD(symval, tee_client_device_id, uuid); As you have mentioned in patch #3: the limitations of TO_NATIVE(), if you can update comments for DEF_FIELD() as well to make it clear that it doesn't support byte arrays/strings would be helpful. I think the following check that you have introduced in patch #3 can still be bypassed for byte arrays/strings. + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ + sizeof(x) == 4 || sizeof(x) == 8, "bug"); BTW, for this fix feel free to add: Reviewed-by: Sumit Garg <sumit.garg@linaro.org> -Sumit > + DEF_FIELD_ADDR(symval, tee_client_device_id, uuid); > > sprintf(alias, "tee:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", > - uuid.b[0], uuid.b[1], uuid.b[2], uuid.b[3], uuid.b[4], > - uuid.b[5], uuid.b[6], uuid.b[7], uuid.b[8], uuid.b[9], > - uuid.b[10], uuid.b[11], uuid.b[12], uuid.b[13], uuid.b[14], > - uuid.b[15]); > + uuid->b[0], uuid->b[1], uuid->b[2], uuid->b[3], uuid->b[4], > + uuid->b[5], uuid->b[6], uuid->b[7], uuid->b[8], uuid->b[9], > + uuid->b[10], uuid->b[11], uuid->b[12], uuid->b[13], uuid->b[14], > + uuid->b[15]); > > add_wildcard(alias); > return 1; > -- > 2.39.2 >
On Mon, Oct 9, 2023 at 3:27 PM Sumit Garg <sumit.garg@linaro.org> wrote: > > Hi Masahiro, > > On Sat, 7 Oct 2023 at 22:34, Masahiro Yamada <masahiroy@kernel.org> wrote: > > > > When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different > > endianness from the target architecture, it results in an incorrect > > MODULE_ALIAS(). > > > > For example, see a case where drivers/char/hw_random/optee-rng.c > > is built as a module. > > > > If you build it on a little endian host, you will get the correct > > MODULE_ALIAS: > > > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > > MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*"); > > > > However, if you build it on a big endian host, you will get a wrong > > MODULE_ALIAS: > > > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > > MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*"); > > > > This issue has been unnoticed because the ARM kernel is most likely built > > on a little endian host (cross-build on x86 or native-build on ARM). > > > > The uuid field must not be reversed because uuid_t is an array of __u8. > > > > To me it wasn't obvious that DEF_FIELD() has certain endianness limitations. > > > Fixes: 0fc1db9d1059 ("tee: add bus driver framework for TEE based devices") > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > --- > > > > scripts/mod/file2alias.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > > index 7056751c29b1..70bf6a2f585c 100644 > > --- a/scripts/mod/file2alias.c > > +++ b/scripts/mod/file2alias.c > > @@ -1348,13 +1348,13 @@ static int do_typec_entry(const char *filename, void *symval, char *alias) > > /* Looks like: tee:uuid */ > > static int do_tee_entry(const char *filename, void *symval, char *alias) > > { > > - DEF_FIELD(symval, tee_client_device_id, uuid); > > As you have mentioned in patch #3: the limitations of TO_NATIVE(), if > you can update comments for DEF_FIELD() as well to make it clear that > it doesn't support byte arrays/strings would be helpful. I think the > following check that you have introduced in patch #3 can still be > bypassed for byte arrays/strings. > > + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ > + sizeof(x) == 4 || sizeof(x) == 8, "bug"); I am afraid you missed the point. bswap_2, bswap_4, bswap_8 do not take a pointer. If you pass an array or a string, it will result in a build error due to the compiler's prototype checking. The kbuild test robot will catch a build error anyway. "You cannot build it in the first place" is better than a comment. > BTW, for this fix feel free to add: > > Reviewed-by: Sumit Garg <sumit.garg@linaro.org> > > -Sumit > > > + DEF_FIELD_ADDR(symval, tee_client_device_id, uuid); > > > > sprintf(alias, "tee:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", > > - uuid.b[0], uuid.b[1], uuid.b[2], uuid.b[3], uuid.b[4], > > - uuid.b[5], uuid.b[6], uuid.b[7], uuid.b[8], uuid.b[9], > > - uuid.b[10], uuid.b[11], uuid.b[12], uuid.b[13], uuid.b[14], > > - uuid.b[15]); > > + uuid->b[0], uuid->b[1], uuid->b[2], uuid->b[3], uuid->b[4], > > + uuid->b[5], uuid->b[6], uuid->b[7], uuid->b[8], uuid->b[9], > > + uuid->b[10], uuid->b[11], uuid->b[12], uuid->b[13], uuid->b[14], > > + uuid->b[15]); > > > > add_wildcard(alias); > > return 1; > > -- > > 2.39.2 > > -- Best Regards Masahiro Yamada
On Mon, 9 Oct 2023 at 12:27, Masahiro Yamada <masahiroy@kernel.org> wrote: > > On Mon, Oct 9, 2023 at 3:27 PM Sumit Garg <sumit.garg@linaro.org> wrote: > > > > Hi Masahiro, > > > > On Sat, 7 Oct 2023 at 22:34, Masahiro Yamada <masahiroy@kernel.org> wrote: > > > > > > When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different > > > endianness from the target architecture, it results in an incorrect > > > MODULE_ALIAS(). > > > > > > For example, see a case where drivers/char/hw_random/optee-rng.c > > > is built as a module. > > > > > > If you build it on a little endian host, you will get the correct > > > MODULE_ALIAS: > > > > > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > > > MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*"); > > > > > > However, if you build it on a big endian host, you will get a wrong > > > MODULE_ALIAS: > > > > > > $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c > > > MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*"); > > > > > > This issue has been unnoticed because the ARM kernel is most likely built > > > on a little endian host (cross-build on x86 or native-build on ARM). > > > > > > The uuid field must not be reversed because uuid_t is an array of __u8. > > > > > > > To me it wasn't obvious that DEF_FIELD() has certain endianness limitations. > > > > > Fixes: 0fc1db9d1059 ("tee: add bus driver framework for TEE based devices") > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > > --- > > > > > > scripts/mod/file2alias.c | 10 +++++----- > > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > > > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c > > > index 7056751c29b1..70bf6a2f585c 100644 > > > --- a/scripts/mod/file2alias.c > > > +++ b/scripts/mod/file2alias.c > > > @@ -1348,13 +1348,13 @@ static int do_typec_entry(const char *filename, void *symval, char *alias) > > > /* Looks like: tee:uuid */ > > > static int do_tee_entry(const char *filename, void *symval, char *alias) > > > { > > > - DEF_FIELD(symval, tee_client_device_id, uuid); > > > > As you have mentioned in patch #3: the limitations of TO_NATIVE(), if > > you can update comments for DEF_FIELD() as well to make it clear that > > it doesn't support byte arrays/strings would be helpful. I think the > > following check that you have introduced in patch #3 can still be > > bypassed for byte arrays/strings. > > > > + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ > > + sizeof(x) == 4 || sizeof(x) == 8, "bug"); > > > > > I am afraid you missed the point. > > bswap_2, bswap_4, bswap_8 do not take a pointer. > > If you pass an array or a string, > it will result in a build error > due to the compiler's prototype checking. > > The kbuild test robot will catch a build error anyway. > I see your point. > > "You cannot build it in the first place" > is better than a comment. > That's fine with me as long as it's a build problem. -Sumit > > > > > > > > > > > BTW, for this fix feel free to add: > > > > Reviewed-by: Sumit Garg <sumit.garg@linaro.org> > > > > -Sumit > > > > > + DEF_FIELD_ADDR(symval, tee_client_device_id, uuid); > > > > > > sprintf(alias, "tee:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", > > > - uuid.b[0], uuid.b[1], uuid.b[2], uuid.b[3], uuid.b[4], > > > - uuid.b[5], uuid.b[6], uuid.b[7], uuid.b[8], uuid.b[9], > > > - uuid.b[10], uuid.b[11], uuid.b[12], uuid.b[13], uuid.b[14], > > > - uuid.b[15]); > > > + uuid->b[0], uuid->b[1], uuid->b[2], uuid->b[3], uuid->b[4], > > > + uuid->b[5], uuid->b[6], uuid->b[7], uuid->b[8], uuid->b[9], > > > + uuid->b[10], uuid->b[11], uuid->b[12], uuid->b[13], uuid->b[14], > > > + uuid->b[15]); > > > > > > add_wildcard(alias); > > > return 1; > > > -- > > > 2.39.2 > > > > > > > -- > Best Regards > Masahiro Yamada
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 7056751c29b1..70bf6a2f585c 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -1348,13 +1348,13 @@ static int do_typec_entry(const char *filename, void *symval, char *alias) /* Looks like: tee:uuid */ static int do_tee_entry(const char *filename, void *symval, char *alias) { - DEF_FIELD(symval, tee_client_device_id, uuid); + DEF_FIELD_ADDR(symval, tee_client_device_id, uuid); sprintf(alias, "tee:%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", - uuid.b[0], uuid.b[1], uuid.b[2], uuid.b[3], uuid.b[4], - uuid.b[5], uuid.b[6], uuid.b[7], uuid.b[8], uuid.b[9], - uuid.b[10], uuid.b[11], uuid.b[12], uuid.b[13], uuid.b[14], - uuid.b[15]); + uuid->b[0], uuid->b[1], uuid->b[2], uuid->b[3], uuid->b[4], + uuid->b[5], uuid->b[6], uuid->b[7], uuid->b[8], uuid->b[9], + uuid->b[10], uuid->b[11], uuid->b[12], uuid->b[13], uuid->b[14], + uuid->b[15]); add_wildcard(alias); return 1;
When MODULE_DEVICE_TABLE(tee, ) is built on a host with a different endianness from the target architecture, it results in an incorrect MODULE_ALIAS(). For example, see a case where drivers/char/hw_random/optee-rng.c is built as a module. If you build it on a little endian host, you will get the correct MODULE_ALIAS: $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c MODULE_ALIAS("tee:ab7a617c-b8e7-4d8f-8301-d09b61036b64*"); However, if you build it on a big endian host, you will get a wrong MODULE_ALIAS: $ grep MODULE_ALIAS drivers/char/hw_random/optee-rng.mod.c MODULE_ALIAS("tee:646b0361-9bd0-0183-8f4d-e7b87c617aab*"); This issue has been unnoticed because the ARM kernel is most likely built on a little endian host (cross-build on x86 or native-build on ARM). The uuid field must not be reversed because uuid_t is an array of __u8. Fixes: 0fc1db9d1059 ("tee: add bus driver framework for TEE based devices") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/mod/file2alias.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)