| Message ID | 20230216070903.355091-1-ajd@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7096deb7b5387e7899655213b7430ab043ddda4f |
| Headers | show |
| Series | powerpc/pseries: Fix endianness issue when parsing PLPKS secvar flags | expand |
On Thu, 16 Feb 2023 18:09:03 +1100, Andrew Donnellan wrote: > When a user updates a variable through the PLPKS secvar interface, we take > the first 8 bytes of the data written to the update attribute to pass > through to the H_PKS_SIGNED_UPDATE hcall as flags. These bytes are always > written in big-endian format. > > Currently, the flags bytes are memcpy()ed into a u64, which is then loaded > into a register to pass as part of the hcall. This means that on LE > systems, the bytes are in the wrong order. > > [...] Applied to powerpc/next. [1/1] powerpc/pseries: Fix endianness issue when parsing PLPKS secvar flags https://git.kernel.org/powerpc/c/7096deb7b5387e7899655213b7430ab043ddda4f cheers
diff --git a/arch/powerpc/platforms/pseries/plpks-secvar.c b/arch/powerpc/platforms/pseries/plpks-secvar.c index f6c8888f4076..257fd1f8bc19 100644 --- a/arch/powerpc/platforms/pseries/plpks-secvar.c +++ b/arch/powerpc/platforms/pseries/plpks-secvar.c @@ -135,7 +135,8 @@ static int plpks_set_variable(const char *key, u64 key_len, u8 *data, goto err; var.namelen = rc * 2; - memcpy(&flags, data, sizeof(flags)); + // Flags are contained in the first 8 bytes of the buffer, and are always big-endian + flags = be64_to_cpup((__be64 *)data); var.datalen = data_size - sizeof(flags); var.data = data + sizeof(flags);
When a user updates a variable through the PLPKS secvar interface, we take the first 8 bytes of the data written to the update attribute to pass through to the H_PKS_SIGNED_UPDATE hcall as flags. These bytes are always written in big-endian format. Currently, the flags bytes are memcpy()ed into a u64, which is then loaded into a register to pass as part of the hcall. This means that on LE systems, the bytes are in the wrong order. Use be64_to_cpup() instead, to ensure the flags bytes are byteswapped if necessary. Reported-by: Stefan Berger <stefanb@linux.ibm.com> Fixes: ccadf154cb00 ("powerpc/pseries: Implement secvars for dynamic secure boot") Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com> --- arch/powerpc/platforms/pseries/plpks-secvar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)