6772d5f2f5
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
39 lines
1.3 KiB
Diff
39 lines
1.3 KiB
Diff
From 6032f0ff672f09babf69d9d42bcde6eb9eeb5bea Mon Sep 17 00:00:00 2001
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From: Daniel Stenberg <daniel@haxx.se>
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Date: Sun, 19 May 2013 23:24:29 +0200
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Subject: [PATCH] Curl_urldecode: no peeking beyond end of input buffer
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Security problem: CVE-2013-2174
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If a program would give a string like "%" to curl_easy_unescape(), it
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would still consider the % as start of an encoded character. The
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function then not only read beyond the buffer but it would also deduct
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the *unsigned* counter variable for how many more bytes there's left to
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read in the buffer by two, making the counter wrap. Continuing this, the
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function would go on reading beyond the buffer and soon writing beyond
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the allocated target buffer...
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Bug: http://curl.haxx.se/docs/adv_20130622.html
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Reported-by: Timo Sirainen
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---
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lib/escape.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/lib/escape.c b/lib/escape.c
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index 6a26cf8..aa7db2c 100644
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--- a/lib/escape.c
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+++ b/lib/escape.c
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@@ -159,7 +159,8 @@ CURLcode Curl_urldecode(struct SessionHandle *data,
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while(--alloc > 0) {
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in = *string;
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- if(('%' == in) && ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
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+ if(('%' == in) && (alloc > 2) &&
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+ ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
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/* this is two hexadecimal digits following a '%' */
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char hexstr[3];
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char *ptr;
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--
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1.7.10.4
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