| Message ID | 2791d4be-ade4-4e50-9b12-33307d8410f6@stanley.mountain (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 991a1b09920bc15c66f64c1e7d15cdabd3816c46 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] eth: fbnic: fix memory corruption in fbnic_tlv_attr_get_string() | expand |
On 3/7/25 1:28 AM, Dan Carpenter wrote: > This code is trying to ensure that the last byte of the buffer is a NUL > terminator. However, the problem is that attr->value[] is an array of > __le32, not char, so it zeroes out 4 bytes way beyond the end of the > buffer. Cast the buffer to char to address this. > > Fixes: e5cf5107c9e4 ("eth: fbnic: Update fbnic_tlv_attr_get_string() to work like nla_strscpy()") > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> > --- > drivers/net/ethernet/meta/fbnic/fbnic_tlv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c > index d558d176e0df..517ed8b2f1cb 100644 > --- a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c > +++ b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c > @@ -261,7 +261,7 @@ ssize_t fbnic_tlv_attr_get_string(struct fbnic_tlv_msg *attr, char *dst, > return -E2BIG; > > srclen = le16_to_cpu(attr->hdr.len) - sizeof(*attr); > - if (srclen > 0 && attr->value[srclen - 1] == '\0') > + if (srclen > 0 && ((char *)attr->value)[srclen - 1] == '\0') > srclen--; > > if (srclen >= dstsize) { Thanks for catching that. While I didn't see any negative effect without it I have verified on hardware this patch works. Reviewed-by: Lee Trager <lee@trager.us>
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Fri, 7 Mar 2025 12:28:48 +0300 you wrote: > This code is trying to ensure that the last byte of the buffer is a NUL > terminator. However, the problem is that attr->value[] is an array of > __le32, not char, so it zeroes out 4 bytes way beyond the end of the > buffer. Cast the buffer to char to address this. > > Fixes: e5cf5107c9e4 ("eth: fbnic: Update fbnic_tlv_attr_get_string() to work like nla_strscpy()") > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> > > [...] Here is the summary with links: - [net-next] eth: fbnic: fix memory corruption in fbnic_tlv_attr_get_string() https://git.kernel.org/netdev/net-next/c/991a1b09920b You are awesome, thank you!
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c index d558d176e0df..517ed8b2f1cb 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_tlv.c @@ -261,7 +261,7 @@ ssize_t fbnic_tlv_attr_get_string(struct fbnic_tlv_msg *attr, char *dst, return -E2BIG; srclen = le16_to_cpu(attr->hdr.len) - sizeof(*attr); - if (srclen > 0 && attr->value[srclen - 1] == '\0') + if (srclen > 0 && ((char *)attr->value)[srclen - 1] == '\0') srclen--; if (srclen >= dstsize) {
This code is trying to ensure that the last byte of the buffer is a NUL terminator. However, the problem is that attr->value[] is an array of __le32, not char, so it zeroes out 4 bytes way beyond the end of the buffer. Cast the buffer to char to address this. Fixes: e5cf5107c9e4 ("eth: fbnic: Update fbnic_tlv_attr_get_string() to work like nla_strscpy()") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> --- drivers/net/ethernet/meta/fbnic/fbnic_tlv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)