On 03.08.21 16:28, Pali Rohár wrote:
Variable xyz.len is set to -1 on error. At the end xyzModem_stream_read() function calls memcpy() with length from variable xyz.len. If this variable is set to -1 then value passed to memcpy is casted to unsigned value, which means to copy whole address space. Which then cause U-Boot crash. E.g. on arm64 it cause CPU crash: "Synchronous Abort" handler, esr 0x96000006
Fix this issue by checking that value stored in xyz.len is valid prior trying to use it.
Signed-off-by: Pali Rohár pali@kernel.org
The changes below seem reasonable.
I would prefer if you could document the elements of struct xyz first. Just add Sphinx style comments to the structure and indicate for element len that a negative value signals an error.
Cf. https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#structure-u...
Acked-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com
common/xyzModem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/common/xyzModem.c b/common/xyzModem.c index fc3459ebbafe..b1b72aae0baf 100644 --- a/common/xyzModem.c +++ b/common/xyzModem.c @@ -494,7 +494,7 @@ xyzModem_stream_read (char *buf, int size, int *err) total = 0; stat = xyzModem_cancel; /* Try and get 'size' bytes into the buffer */
- while (!xyz.at_eof && (size > 0))
- while (!xyz.at_eof && xyz.len >= 0 && (size > 0)) { if (xyz.len == 0) {
@@ -587,7 +587,7 @@ xyzModem_stream_read (char *buf, int size, int *err) } } /* Don't "read" data from the EOF protocol package */
if (!xyz.at_eof)
if (!xyz.at_eof && xyz.len > 0)