74 lines
2.5 KiB
Diff
74 lines
2.5 KiB
Diff
From 5e75160f48785464f9213c6bc8c72b9372c5318b Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Sat, 23 May 2020 13:18:51 +0200
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Subject: [PATCH] blobmsg: fix attrs iteration in the blobmsg_check_array_len()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Starting with 75e300aeec25 ("blobmsg: fix wrong payload len passed from
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blobmsg_check_array") blobmsg_check_array_len() gets *blob* length
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passed as argument. It cannot be used with __blobmsg_for_each_attr()
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which expects *data* length.
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Use blobmsg_for_each_attr() which calculates *data* length on its own.
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The same bug was already reported in the past and there was fix attempt
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in the commit cd75136b1342 ("blobmsg: fix wrong payload len passed from
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blobmsg_check_array"). That change made blobmsg_check_attr_len() calls
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fail however.
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This is hopefully the correct & complete fix:
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1. blobmsg_check_array_len() gets *blob* length
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2. It calls blobmsg_check_attr_len() which requires *blob* length
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3. It uses blobmsg_for_each_attr() which gets *data* length
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This fixes iterating over random memory treated as attrs. That was
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resulting in check failing randomly for totally correct blobs. It's
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critical e.g. for procd project with its instance_fill_array() failing
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and procd not starting services.
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Fixes: 75e300aeec25 ("blobmsg: fix wrong payload len passed from blobmsg_check_array")
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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---
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blobmsg.c | 10 ++++++----
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1 file changed, 6 insertions(+), 4 deletions(-)
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--- a/blobmsg.c
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+++ b/blobmsg.c
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@@ -123,16 +123,18 @@ int blobmsg_check_array(const struct blo
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return blobmsg_check_array_len(attr, type, blob_len(attr));
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}
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-int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len)
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+int blobmsg_check_array_len(const struct blob_attr *attr, int type,
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+ size_t blob_len)
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{
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struct blob_attr *cur;
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+ size_t rem;
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bool name;
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int size = 0;
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if (type > BLOBMSG_TYPE_LAST)
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return -1;
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- if (!blobmsg_check_attr_len(attr, false, len))
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+ if (!blobmsg_check_attr_len(attr, false, blob_len))
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return -1;
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switch (blobmsg_type(attr)) {
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@@ -146,11 +148,11 @@ int blobmsg_check_array_len(const struct
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return -1;
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}
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- __blobmsg_for_each_attr(cur, attr, len) {
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+ blobmsg_for_each_attr(cur, attr, rem) {
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if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
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return -1;
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- if (!blobmsg_check_attr_len(cur, name, len))
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+ if (!blobmsg_check_attr_len(cur, name, rem))
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return -1;
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size++;
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