| Message ID | 20210421234908.12817-1-a@unstable.cc |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [Openvpn-devel] options: check for blanks in fingerprints and reject string if found | expand |
Am 22.04.21 um 01:49 schrieb Antonio Quartulli: > From: Antonio Quartulli <antonio@openvpn.net> > > A fingerprint is not expected to contains any blank (white space), > howeveri, the parser routine will still attempt parsing the octect > and ignore the space. > > This means that a fingerprint like > 5 :F0:A8:75:70:46:6E:0B:A2:31:53:88:0B:0E:8C:E4:8A:5E:BF:1E:08:16:16:41:63:2C:B5:F4:D2:73:9F:E5 > will be parsed successfully. > > Explcitly check for spaces in the various octects, before conversion, > and error out if any is found. Explicitly > > Signed-off-by: Antonio Quartulli <antonio@openvpn.net> > --- > src/openvpn/options.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/src/openvpn/options.c b/src/openvpn/options.c > index 817a1533..264fe383 100644 > --- a/src/openvpn/options.c > +++ b/src/openvpn/options.c > @@ -1099,6 +1099,18 @@ parse_hash_fingerprint(const char *str, int nbytes, int msglevel, struct gc_aren > bs[0] = *cp++; > bs[1] = *cp++; > bs[2] = 0; > + > + /* the format string "%x" passed to sscanf will ignore any space and > + * will still try to parse the other character. However, this is not > + * expected format for a fingerprint, therefore explcitly check for explicitly > + * blanks in the string and error out if any is found > + */ > + if (bs[0] == ' ' || bs[1] == ' ') > + { > + msg(msglevel, "format error in hash fingerprint unexpected blank: %s", > + str); > + } > + > byte = 0; > if (sscanf(bs, "%x", &byte) != 1) > { > I would not have spend the time to fix this but since Antonio done it: Acked-By: Arne Schwabe <arne@rfc2549.org>
Your patch has been applied to the master branch.
That said, I find this function pretty insane, tbh. Parsing a sequence
of double-digit hex bytes should be doable in half the lines of code,
and without needing to copy bytes to temp buffers to pass to scanf()...
(https://stackoverflow.com/questions/10156409/convert-hex-string-char-to-int)
commit 9e71cf13134c10bb7e952e3dadbcc79884f60b93
Author: Antonio Quartulli
Date: Thu Apr 22 01:49:08 2021 +0200
options: check for blanks in fingerprints and reject string if found
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20210421234908.12817-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22182.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
--
kind regards,
Gert Doering
diff --git a/src/openvpn/options.c b/src/openvpn/options.c index 817a1533..264fe383 100644 --- a/src/openvpn/options.c +++ b/src/openvpn/options.c @@ -1099,6 +1099,18 @@ parse_hash_fingerprint(const char *str, int nbytes, int msglevel, struct gc_aren bs[0] = *cp++; bs[1] = *cp++; bs[2] = 0; + + /* the format string "%x" passed to sscanf will ignore any space and + * will still try to parse the other character. However, this is not + * expected format for a fingerprint, therefore explcitly check for + * blanks in the string and error out if any is found + */ + if (bs[0] == ' ' || bs[1] == ' ') + { + msg(msglevel, "format error in hash fingerprint unexpected blank: %s", + str); + } + byte = 0; if (sscanf(bs, "%x", &byte) != 1) {