From: Jean Delvare <jdelvare@suse.de> stable inclusion from stable-v5.10.210 commit 7a14b8a477b88607d157c24aeb23e7389ec3319f category: bugfix bugzilla: 189550 CVE: CVE-2024-26593 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit c1c9d0f6f7f1dbf29db996bd8e166242843a5f21 ] According to the Intel datasheets, software must reset the block buffer index twice for block process call transactions: once before writing the outgoing data to the buffer, and once again before reading the incoming data from the buffer. The driver is currently missing the second reset, causing the wrong portion of the block buffer to be read. Signed-off-by: Jean Delvare <jdelvare@suse.de> Reported-by: Piotr Zakowski <piotr.zakowski@intel.com> Closes: https://lore.kernel.org/linux-i2c/20240213120553.7b0ab120@endymion.delvare/ Fixes: 315cd67c9453 ("i2c: i801: Add Block Write-Block Read Process Call support") Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com> Signed-off-by: Andi Shyti <andi.shyti@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Liao Chen <liaochen4@huawei.com> --- drivers/i2c/busses/i2c-i801.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index fa346be107f7..39b913bcaca6 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -542,12 +542,11 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return -EOPNOTSUPP; } - inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ - /* Use 32-byte buffer to process this transaction */ if (read_write == I2C_SMBUS_WRITE) { len = data->block[0]; outb_p(len, SMBHSTDAT0(priv)); + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) outb_p(data->block[i+1], SMBBLKDAT(priv)); } @@ -563,6 +562,7 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return -EPROTO; data->block[0] = len; + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) data->block[i + 1] = inb_p(SMBBLKDAT(priv)); } -- 2.34.1