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bus: fix bloom_add_prefixes() to add all required data

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Lets look at an example where we add arg0="/foo/bar/waldo" to a
bloom-filter. The following strings are added:
  "arg0:/foo/bar/waldo"
  "arg0-slash-prefix:/foo/bar"
  "arg0-slash-prefix:/foo"

Two problems arise:

1) If we match on "arg0path=/foo/bar/waldo", the dbus-spec explicitly
states that equal strings are also considered prefixes. However, in the
bloom-match, we can only provide a single match-filter. Therefore, we have
to add "arg0-slash-prefix:/foo/bar/waldo" there, but this never occured in
the bloom-mask of the message.
Hence, this patch makes sure bloom_add_prefixes() adds the full path as
prefix, too.

2) If we match on "arg0path=/foo/", the dbus-spec states that arg0path
does prefix-matching with the trailing slash _included_, unlike
path_namespace= matches, which does *not* include them. This is
inconsistent, but we have to support the specs. Therefore, we must add
prefixes with _and_ without trailing separators.
Hence, this patch makes sure bloom_add_prefixes() adds all prefixes with
the trailing slash included.

The final set of strings added therefore is:
  "arg0:/foo/bar/waldo"
  "arg0-slash-prefix:/foo/bar/waldo"
  "arg0-slash-prefix:/foo/bar/"
  "arg0-slash-prefix:/foo/bar"
  "arg0-slash-prefix:/foo/"
  "arg0-slash-prefix:/foo"
  "arg0-slash-prefix:/"
This commit is contained in:
David Herrmann 2015-06-10 18:26:16 +02:00
parent a8467435a0
commit 7cd4dbe9ca
1 changed files with 9 additions and 1 deletions
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10
src/libsystemd/sd-bus/bus-bloom.c
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@ -116,11 +116,19 @@ void bloom_add_prefixes(uint64_t filter[], size_t size, unsigned k, const char *
p = stpcpy(stpcpy(c, a), ":");
strcpy(p, b);
bloom_add_data(filter, size, k, c, n);
for (;;) {
char *e;
e = strrchr(p, sep);
if (!e || e == p)
if (!e)
break;
*(e + 1) = 0;
bloom_add_data(filter, size, k, c, e - c + 1);
if (e == p)
break;
*e = 0;