CVE-2026-80712

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> spi: spi-qpic-snand: write the feature value before executing SET_FEATURE<br /> <br /> qcom_spi_send_cmdaddr() programs NAND_FLASH_CMD/NAND_EXEC_CMD and submits<br /> the descriptors, which makes the controller execute the command<br /> immediately. For SPINAND_SET_FEATURE the value to be written is only<br /> placed into NAND_FLASH_FEATURES afterwards, by qcom_spi_io_op(), in a<br /> second submission - so the chip is programmed with whatever that register<br /> happened to hold from a previous operation, and the intended value is only<br /> applied by the *next* SET_FEATURE.<br /> <br /> Measured on a TP-Link Archer AX55 v1 (IPQ5018, ESMT F50L1G41LB): writing<br /> 0x40 to the configuration register (0xb0) leaves the chip at 0x00, and the<br /> subsequent write of 0x00 leaves it at 0x40 - every write lands one<br /> operation late.<br /> <br /> This stayed unnoticed until v6.18 added SPI-NAND OTP support together<br /> with OTP entries for ESMT chips. spinand_otp_rw() enables OTP mode,<br /> reads, and disables it again, and mtd_otp_nvmem_add() does this during<br /> MTD registration. With the off-by-one, the "disable" write actually<br /> applies the previously requested value, so CFG_OTP_ENABLE ends up set:<br /> the chip stays in OTP mode, every subsequent array read returns the OTP<br /> area instead of the array (UBI reports an empty device) and all writes<br /> fail with -EIO because the OTP area is write protected. On this board<br /> that makes the whole flash unusable and the device unbootable.<br /> <br /> Write the feature value into NAND_FLASH_FEATURES as part of the same<br /> transaction, before NAND_EXEC_CMD. While at it, copy only the bytes the<br /> operation actually carries - the previous code dereferenced a 4-byte<br /> pointer on a one-byte buffer (spinand-&gt;scratchbuf).<br /> <br /> With this patch the flash contents read back bit-identical to a<br /> known-good dump of the same board taken under the vendor firmware<br /> (md5-verified across partitions), and writes work.