From 7096deb7b5387e7899655213b7430ab043ddda4f Mon Sep 17 00:00:00 2001 From: Andrew Donnellan Date: Thu, 16 Feb 2023 18:09:03 +1100 Subject: [PATCH] powerpc/pseries: Fix endianness issue when parsing PLPKS secvar 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 Fixes: ccadf154cb00 ("powerpc/pseries: Implement secvars for dynamic secure boot") Signed-off-by: Andrew Donnellan Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230216070903.355091-1-ajd@linux.ibm.com --- arch/powerpc/platforms/pseries/plpks-secvar.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/pseries/plpks-secvar.c b/arch/powerpc/platforms/pseries/plpks-secvar.c index f6c8888..257fd1f 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); -- 2.7.4