From 22c7a18ed5f007faccb7527bc890463763214081 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 25 Mar 2021 10:32:50 +0200 Subject: [PATCH] thunderbolt: usb4: Fix NVM read buffer bounds and offset issue Up to 64 bytes of data can be read from NVM in one go. Read address must be dword aligned. Data is read into a local buffer. If caller asks to read data starting at an unaligned address then full dword is anyway read from NVM into a local buffer. Data is then copied from the local buffer starting at the unaligned offset to the caller buffer. In cases where asked data length + unaligned offset is over 64 bytes we need to make sure we don't read past the 64 bytes in the local buffer when copying to caller buffer, and make sure that we don't skip copying unaligned offset bytes from local buffer anymore after the first round of 64 byte NVM data read. Fixes: b04079837b20 ("thunderbolt: Add initial support for USB4") Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman Signed-off-by: Mika Westerberg --- drivers/thunderbolt/usb4.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c index 680bc73..671d72a 100644 --- a/drivers/thunderbolt/usb4.c +++ b/drivers/thunderbolt/usb4.c @@ -68,15 +68,15 @@ static int usb4_do_read_data(u16 address, void *buf, size_t size, unsigned int retries = USB4_DATA_RETRIES; unsigned int offset; - offset = address & 3; - address = address & ~3; - do { - size_t nbytes = min_t(size_t, size, USB4_DATA_DWORDS * 4); unsigned int dwaddress, dwords; u8 data[USB4_DATA_DWORDS * 4]; + size_t nbytes; int ret; + offset = address & 3; + nbytes = min_t(size_t, size + offset, USB4_DATA_DWORDS * 4); + dwaddress = address / 4; dwords = ALIGN(nbytes, 4) / 4; @@ -87,6 +87,7 @@ static int usb4_do_read_data(u16 address, void *buf, size_t size, return ret; } + nbytes -= offset; memcpy(buf, data + offset, nbytes); size -= nbytes; -- 2.7.4