Messages in this thread Patch in this message | | | Subject | [PATCH 15/18] certs: Fix blacklisted hexadecimal hash string check | From | David Howells <> | Date | Wed, 09 Dec 2020 12:16:21 +0000 |
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From: Mickaël Salaün <mic@linux.microsoft.com>
When looking for a blacklisted hash, bin2hex() is used to transform a binary hash to an ascii (lowercase) hexadecimal string. This string is then search for in the description of the keys from the blacklist keyring. When adding a key to the blacklist keyring, blacklist_vet_description() checks the hash prefix and the hexadecimal string, but not that this string is lowercase. It is then valid to set hashes with uppercase hexadecimal, which will be silently ignored by the kernel.
Add an additional check to blacklist_vet_description() to check that hexadecimal strings are in lowercase.
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> ---
certs/blacklist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/certs/blacklist.c b/certs/blacklist.c index 2719fb2fbc1c..a888b934a1cd 100644 --- a/certs/blacklist.c +++ b/certs/blacklist.c @@ -37,7 +37,7 @@ static int blacklist_vet_description(const char *desc) found_colon: desc++; for (; *desc; desc++) { - if (!isxdigit(*desc)) + if (!isxdigit(*desc) || isupper(*desc)) return -EINVAL; n++; }
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