From: Linus Walleij linus.walleij@linaro.org
stable inclusion from stable-v6.6.3 commit 63fbcea8d0d9f68583d4f4a0988b44f3171a6d0c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 565fe150624ee77dc63a735cc1b3bff5101f38a3 upstream.
Currently the offset into the device when looking for OTP bits can go outside of the address of the MTD NOR devices, and if that memory isn't readable, bad things happen on the IXP4xx (added prints that illustrate the problem before the crash):
cfi_intelext_otp_walk walk OTP on chip 0 start at reg_prot_offset 0x00000100 ixp4xx_copy_from copy from 0x00000100 to 0xc880dd78 cfi_intelext_otp_walk walk OTP on chip 0 start at reg_prot_offset 0x12000000 ixp4xx_copy_from copy from 0x12000000 to 0xc880dd78 8<--- cut here --- Unable to handle kernel paging request at virtual address db000000 [db000000] *pgd=00000000 (...)
This happens in this case because the IXP4xx is big endian and the 32- and 16-bit fields in the struct cfi_intelext_otpinfo are not properly byteswapped. Compare to how the code in read_pri_intelext() byteswaps the fields in struct cfi_pri_intelext.
Adding a small byte swapping loop for the OTP in read_pri_intelext() and the crash goes away.
The problem went unnoticed for many years until I enabled CONFIG_MTD_OTP on the IXP4xx as well, triggering the bug.
Cc: stable@vger.kernel.org Reviewed-by: Nicolas Pitre nico@fluxnic.net Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Link: https://lore.kernel.org/linux-mtd/20231020-mtd-otp-byteswap-v4-1-0d132c06aa9... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/mtd/chips/cfi_cmdset_0001.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c index 11b06fefaa0e..c10693ba265b 100644 --- a/drivers/mtd/chips/cfi_cmdset_0001.c +++ b/drivers/mtd/chips/cfi_cmdset_0001.c @@ -422,9 +422,25 @@ read_pri_intelext(struct map_info *map, __u16 adr) extra_size = 0;
/* Protection Register info */ - if (extp->NumProtectionFields) + if (extp->NumProtectionFields) { + struct cfi_intelext_otpinfo *otp = + (struct cfi_intelext_otpinfo *)&extp->extra[0]; + extra_size += (extp->NumProtectionFields - 1) * - sizeof(struct cfi_intelext_otpinfo); + sizeof(struct cfi_intelext_otpinfo); + + if (extp_size >= sizeof(*extp) + extra_size) { + int i; + + /* Do some byteswapping if necessary */ + for (i = 0; i < extp->NumProtectionFields - 1; i++) { + otp->ProtRegAddr = le32_to_cpu(otp->ProtRegAddr); + otp->FactGroups = le16_to_cpu(otp->FactGroups); + otp->UserGroups = le16_to_cpu(otp->UserGroups); + otp++; + } + } + } }
if (extp->MinorVersion >= '1') {