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author | Daniel P. Berrange <berrange@redhat.com> | 2015-11-23 15:24:50 +0000 |
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committer | Daniel P. Berrange <berrange@redhat.com> | 2015-12-18 16:25:08 +0000 |
commit | 89bc0b6cae6e40e9247bf911162b0aee0c818c4c (patch) | |
tree | be3ea0fed48a497e04e74b999d63e979faed3eea /util/base64.c | |
parent | 18f49881cf8359e89396aac12f5d3cf3f8a632ba (diff) | |
download | qemu-89bc0b6cae6e40e9247bf911162b0aee0c818c4c.zip qemu-89bc0b6cae6e40e9247bf911162b0aee0c818c4c.tar.gz qemu-89bc0b6cae6e40e9247bf911162b0aee0c818c4c.tar.bz2 |
util: add base64 decoding function
The standard glib provided g_base64_decode doesn't provide any
kind of sensible error checking on its input. Add a QEMU custom
wrapper qbase64_decode which can be used with untrustworthy
input that can contain invalid base64 characters, embedded
NUL characters, or not be NUL terminated at all.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'util/base64.c')
-rw-r--r-- | util/base64.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/util/base64.c b/util/base64.c new file mode 100644 index 0000000..f82caa7 --- /dev/null +++ b/util/base64.c @@ -0,0 +1,60 @@ +/* + * QEMU base64 helpers + * + * Copyright (c) 2015 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <config-host.h> + +#include "qemu/base64.h" + +static const char *base64_valid_chars = + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"; + +uint8_t *qbase64_decode(const char *input, + size_t in_len, + size_t *out_len, + Error **errp) +{ + *out_len = 0; + + if (in_len != -1) { + /* Lack of NUL terminator is an error */ + if (input[in_len] != '\0') { + error_setg(errp, "Base64 data is not NUL terminated"); + return NULL; + } + /* Check there's no NULs embedded since we expect + * this to be valid base64 data */ + if (memchr(input, '\0', in_len) != NULL) { + error_setg(errp, "Base64 data contains embedded NUL characters"); + return NULL; + } + + /* Now we know its a valid nul terminated string + * strspn is safe to use... */ + } else { + in_len = strlen(input); + } + + if (strspn(input, base64_valid_chars) != in_len) { + error_setg(errp, "Base64 data contains invalid characters"); + return NULL; + } + + return g_base64_decode(input, out_len); +} |