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Audit: fix handling of 'strings' with NULL characters 

currently audit_log_n_untrustedstring() uses audit_string_contains_control()
to check if the 'string' has any control characters.  If the 'string' has an
embedded NULL audit_string_contains_control() will return that the data has
no control characters and will then pass the string to audit_log_n_string
with the total length, not the length up to the first NULL.
audit_log_n_string() does a memcpy of the entire length and so the actual
audit record emitted may then contain a NULL and then whatever random memory
is after the NULL.

Since we want to log the entire octet stream (if we can't trust the data
to be a string we can't trust that a NULL isn't actually a part of it)
we should just consider NULL as a control character.  If the caller is
certain they want to stop at the first NULL they should be using
audit_log_untrustedstring.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
hifive-unleashed-5.1
Miloslav Trmac 2009-03-19 09:48:27 -04:00 committed by Al Viro
parent c28bb7da74
commit b3897f5671
1 changed files with 1 additions and 1 deletions
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2
kernel/audit.c
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@ -1382,7 +1382,7 @@ void audit_log_n_string(struct audit_buffer *ab, const char *string,
int audit_string_contains_control(const char *string, size_t len)
{
const unsigned char *p;
for (p = string; p < (const unsigned char *)string + len && *p; p++) {
for (p = string; p < (const unsigned char *)string + len; p++) {
if (*p == '"' || *p < 0x21 || *p > 0x7e)
return 1;
}