[PATCH 4.4 04/66] qlge: avoid memcpy buffer overflow

Greg Kroah-Hartman
2017-09-24T21:29:02Z

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit e58f95831e7468d25eb6e41f234842ecfe6f014f ]

gcc-8.0.0 (snapshot) points out that we copy a variable-length string
into a fixed length field using memcpy() with the destination length,
and that ends up copying whatever follows the string:

inlined from 'ql_core_dump' at drivers/net/ethernet/qlogic/qlge/qlge_dbg.c:1106:2:
drivers/net/ethernet/qlogic/qlge/qlge_dbg.c:708:2: error: 'memcpy' reading 15 bytes from a region of size 14 [-Werror=stringop-overflow=]
memcpy(seg_hdr->description, desc, (sizeof(seg_hdr->description)) - 1);

Changing it to use strncpy() will instead zero-pad the destination,
which seems to be the right thing to do here.

The bug is probably harmless, but it seems like a good idea to address
it in stable kernels as well, if only for the purpose of building with
gcc-8 without warnings.

Fixes: a61f80261306 ("qlge: Add ethtool register dump function.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/qlogic/qlge/qlge_dbg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/qlogic/qlge/qlge_dbg.c
+++ b/drivers/net/ethernet/qlogic/qlge/qlge_dbg.c
@@ -724,7 +724,7 @@ static void ql_build_coredump_seg_header
seg_hdr->cookie = MPI_COREDUMP_COOKIE;
seg_hdr->segNum = seg_number;
seg_hdr->segSize = seg_size;
- memcpy(seg_hdr->description, desc, (sizeof(seg_hdr->description)) - 1);
+ strncpy(seg_hdr->description, desc, (sizeof(seg_hdr->description)) - 1);
}

/*