File gnupg-2.1.0-boo-907198-openpgp_oid_to_str-buffe... of Package gpg2

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File gnupg-2.1.0-boo-907198-openpgp_oid_to_str-buffer-overflow.patch of Package gpg2 (Revision 986da3bbac5f6ee100558f34c0fd4e9d)

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From: Werner Koch <wk@gnupg.org>
Date: Tue, 25 Nov 2014 11:58:56 +0100
Subject: [PATCH] Fix buffer overflow in openpgp_oid_to_str.
References: boo#907198 http://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=commit;h=8445ef24fc31e1fe0291e17f90f9f06b536e34da
Upstream: committed

* common/openpgp-oid.c (openpgp_oid_to_str): Fix unsigned underflow.

* common/t-openpgp-oid.c (BADOID): New.
(test_openpgp_oid_to_str): Add test cases.
--

The code has an obvious error by not considering invalid encoding for
arc-2.  A first byte of 0x80 can be used to make a value of less then
80 and we then subtract 80 from that value as required by the OID
encoding rules.  Due to the unsigned integer this results in a pretty
long value which won't fit anymore into the allocated buffer.

The fix is obvious.  Also added a few simple test cases.  Note that we
keep on using sprintf instead of snprintf because managing the
remaining length of the buffer would probably be more error prone than
assuring that the buffer is large enough.  Getting rid of sprintf
altogether by using direct conversion along with membuf_t like code
might be possible.

Reported-by: Hanno Böck
Signed-off-by: Werner Koch <wk@gnupg.org>

Ported from libksba commit f715b9e156dfa99ae829fc694e5a0abd23ef97d7
---
 common/openpgp-oid.c   |    2 ++
 common/t-openpgp-oid.c |    9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/common/openpgp-oid.c b/common/openpgp-oid.c
index 010c23f..d3d1f2a 100644
--- a/common/openpgp-oid.c
+++ b/common/openpgp-oid.c
@@ -236,6 +236,8 @@ openpgp_oid_to_str (gcry_mpi_t a)
         val <<= 7;
         val |= buf[n] & 0x7f;
       }
+    if (val < 80)
+      goto badoid;
     val -= 80;
     sprintf (p, "2.%lu", val);
     p += strlen (p);
diff --git a/common/t-openpgp-oid.c b/common/t-openpgp-oid.c
index 79e5a70..5cd778d 100644
--- a/common/t-openpgp-oid.c
+++ b/common/t-openpgp-oid.c
@@ -32,6 +32,9 @@
   } while(0)
 
 
+#define BADOID "1.3.6.1.4.1.11591.2.12242973"
+
+
 static void
 test_openpgp_oid_from_str (void)
 {
@@ -108,6 +111,12 @@ test_openpgp_oid_to_str (void)
     { "1.3.132.0.35",
       { 5, 0x2B, 0x81, 0x04, 0x00, 0x23 }},
 
+    { BADOID,
+      { 9, 0x80, 0x02, 0x70, 0x50, 0x25, 0x46, 0xfd, 0x0c, 0xc0 }},
+
+    { BADOID,
+      { 1, 0x80 }},
+
     { NULL }};
   gcry_mpi_t a;
   int idx;
-- 
1.7.10.4

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File gnupg-2.1.0-boo-907198-openpgp_oid_to_str-buffer-overflow.patch of Package gpg2 (Revision 986da3bbac5f6ee100558f34c0fd4e9d)

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