[flashrom-gerrit] Change in ...flashrom[1.0.x]: dediprog: Fix small, unaligned reads

[Nico Huber (Code Review)]

Nico Huber has submitted this change and it was merged. ( https://review.coreboot.org/c/flashrom/+/30380 )

Change subject: dediprog: Fix small, unaligned reads
......................................................................

dediprog: Fix small, unaligned reads

This never was a use case until now but the `--fmap` code makes it
obvious: Unaligned reads that were smaller than the `chunksize` here,
were extended without considering the length of the buffer read into.

With that fixed we run into the next problem: dediprog_spi_bulk_read()
shouldn't report an error when an empty read is unaligned.

Change-Id: Ie12b62499ebfdb467d5126c00d327c76077ddead
Signed-off-by: Nico Huber 
Reviewed-on: https://review.coreboot.org/c/30051
Tested-by: build bot (Jenkins) 
Reviewed-by: David Hendricks 
Reviewed-on: https://review.coreboot.org/c/30380
Reviewed-by: Nico Huber 
---
M dediprog.c
1 file changed, 4 insertions(+), 4 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, approved

diff --git a/dediprog.c b/dediprog.c
index 2f5b441..70660d4 100644
--- a/dediprog.c
+++ b/dediprog.c
@@ -425,15 +425,15 @@
    struct libusb_transfer *transfers[DEDIPROG_ASYNC_TRANSFERS] = { NULL, };
    struct libusb_transfer *transfer;

+	if (len == 0)
+		return 0;
+
    if ((start % chunksize) || (len % chunksize)) {
    	msg_perr("%s: Unaligned start=%i, len=%i! Please report a bug at [e-mail]\n",
    		 __func__, start, len);
    	return 1;
    }

-	if (len == 0)
-		return 0;
-
    /* Command packet size of protocols: new 10 B, old 5 B. */
    uint8_t data_packet[is_new_prot() ? 10 : 5];
    unsigned int value, idx;
@@ -503,7 +503,7 @@
    int ret;
    /* chunksize must be 512, other sizes will NOT work at all. */
    const unsigned int chunksize = 0x200;
-	unsigned int residue = start % chunksize ? chunksize - start % chunksize : 0;
+	unsigned int residue = start % chunksize ? min(len, chunksize - start % chunksize) : 0;
    unsigned int bulklen;

dediprog_set_leds(LED_BUSY);