Initial commit
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@@ -0,0 +1,78 @@
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From b6a0a070f2e14808e835c2fcfa3820a55041902f Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Petr=20=C5=A0tetiar?= <ynezz@true.cz>
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Date: Mon, 9 Dec 2019 14:11:45 +0100
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Subject: blob: introduce blob_parse_untrusted
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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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blob_parse can be only used on trusted input as it has no possibility to
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check the length of the provided input buffer, which might lead to
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undefined behaviour and/or crashes when supplied with malformed,
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corrupted or otherwise specially crafted input.
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So this introduces blob_parse_untrusted variant which expects additional
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input buffer length argument and thus should be able to process also
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inputs from untrusted sources.
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Signed-off-by: Petr Štetiar <ynezz@true.cz>
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---
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blob.c | 24 ++++++++++++++++++++++++
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blob.h | 7 +++++++
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2 files changed, 31 insertions(+)
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--- a/blob.c
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+++ b/blob.c
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@@ -253,6 +253,30 @@ blob_parse_attr(struct blob_attr *attr,
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}
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int
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+blob_parse_untrusted(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max)
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+{
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+ struct blob_attr *pos;
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+ size_t len = 0;
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+ int found = 0;
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+ size_t rem;
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+
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+ if (!attr || attr_len < sizeof(struct blob_attr))
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+ return 0;
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+
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+ len = blob_raw_len(attr);
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+ if (len != attr_len)
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+ return 0;
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+
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+ memset(data, 0, sizeof(struct blob_attr *) * max);
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+ blob_for_each_attr_len(pos, attr, len, rem) {
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+ found += blob_parse_attr(pos, rem, data, info, max);
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+ }
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+
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+ return found;
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+}
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+
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+/* use only on trusted input, otherwise consider blob_parse_untrusted */
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+int
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blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max)
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{
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struct blob_attr *pos;
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--- a/blob.h
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+++ b/blob.h
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@@ -199,6 +199,7 @@ extern void blob_nest_end(struct blob_bu
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extern struct blob_attr *blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len);
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extern bool blob_check_type(const void *ptr, unsigned int len, int type);
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extern int blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max);
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+extern int blob_parse_untrusted(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max);
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extern struct blob_attr *blob_memdup(struct blob_attr *attr);
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extern struct blob_attr *blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len);
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@@ -254,5 +255,11 @@ blob_put_u64(struct blob_buf *buf, int i
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(blob_pad_len(pos) >= sizeof(struct blob_attr)); \
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rem -= blob_pad_len(pos), pos = blob_next(pos))
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+#define blob_for_each_attr_len(pos, attr, attr_len, rem) \
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+ for (rem = attr ? blob_len(attr) : 0, \
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+ pos = (struct blob_attr *) (attr ? blob_data(attr) : NULL); \
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+ rem >= sizeof(struct blob_attr) && rem < attr_len && (blob_pad_len(pos) <= rem) && \
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+ (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
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+ rem -= blob_pad_len(pos), pos = blob_next(pos))
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#endif
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