tools: ynl-gen: validate 0 len strings from kernel

[ Upstream commit 4720f9707c783f642332dee3d56dccaefa850e42 ]

Strings from the kernel are guaranteed to be null terminated and
ynl_attr_validate() checks for this. But it doesn't check if the string
has a len of 0, which would cause problems when trying to access
data[len - 1]. Fix this by checking that len is positive.

Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://patch.msgid.link/20250503043050.861238-1-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Wei 2025-05-02 21:30:50 -07:00 committed by Greg Kroah-Hartman
parent 50d0de59f6
commit 4e3401aa6e

View File

@ -368,7 +368,7 @@ int ynl_attr_validate(struct ynl_parse_arg *yarg, const struct nlattr *attr)
"Invalid attribute (binary %s)", policy->name);
return -1;
case YNL_PT_NUL_STR:
if ((!policy->len || len <= policy->len) && !data[len - 1])
if (len && (!policy->len || len <= policy->len) && !data[len - 1])
break;
yerr(yarg->ys, YNL_ERROR_ATTR_INVALID,
"Invalid attribute (string %s)", policy->name);