This is a note to let you know that I've just added the patch titled
netfilter: x_tables: check standard target size too
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-x_tables-check-standard-target-size-too.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@xxxxxxxxx>
Date: Fri, 1 Apr 2016 14:17:27 +0200
Subject: netfilter: x_tables: check standard target size too
From: Florian Westphal <fw@xxxxxxxxx>
commit 7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44 upstream.
We have targets and standard targets -- the latter carries a verdict.
The ip/ip6tables validation functions will access t->verdict for the
standard targets to fetch the jump offset or verdict for chainloop
detection, but this happens before the targets get checked/validated.
Thus we also need to check for verdict presence here, else t->verdict
can point right after a blob.
Spotted with UBSAN while testing malformed blobs.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netfilter/x_tables.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -539,6 +539,13 @@ int xt_compat_match_to_user(const struct
}
EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
+/* non-compat version may have padding after verdict */
+struct compat_xt_standard_target {
+ struct compat_xt_entry_target t;
+ compat_uint_t verdict;
+};
+
+/* see xt_check_entry_offsets */
int xt_compat_check_entry_offsets(const void *base,
unsigned int target_offset,
unsigned int next_offset)
@@ -556,6 +563,10 @@ int xt_compat_check_entry_offsets(const
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
+ if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
+ target_offset + sizeof(struct compat_xt_standard_target) != next_offset)
+ return -EINVAL;
+
return 0;
}
EXPORT_SYMBOL(xt_compat_check_entry_offsets);
@@ -595,6 +606,10 @@ int xt_check_entry_offsets(const void *b
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
+ if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
+ target_offset + sizeof(struct xt_standard_target) != next_offset)
+ return -EINVAL;
+
return 0;
}
EXPORT_SYMBOL(xt_check_entry_offsets);
Patches currently in stable-queue which might be from fw@xxxxxxxxx are
queue-4.4/netfilter-x_tables-add-and-use-xt_check_entry_offsets.patch
queue-4.4/netfilter-x_tables-assert-minimum-target-size.patch
queue-4.4/netfilter-x_tables-add-compat-version-of-xt_check_entry_offsets.patch
queue-4.4/netfilter-x_tables-check-for-bogus-target-offset.patch
queue-4.4/netfilter-x_tables-validate-e-target_offset-early.patch
queue-4.4/netfilter-x_tables-validate-targets-of-jumps.patch
queue-4.4/netfilter-x_tables-don-t-move-to-non-existent-next-rule.patch
queue-4.4/netfilter-x_tables-kill-check_entry-helper.patch
queue-4.4/netfilter-x_tables-make-sure-e-next_offset-covers-remaining-blob-size.patch
queue-4.4/netfilter-x_tables-check-standard-target-size-too.patch
queue-4.4/netfilter-x_tables-validate-all-offsets-and-sizes-in-a-rule.patch
queue-4.4/netfilter-x_tables-fix-unconditional-helper.patch
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