On 9/10/19 3:53 PM, Mike Palmiotto wrote:
Commit c19395d72295f5e69275d98df5db22dfdf214b6c fixed some handling of unknown
classes/permissions, but missed the case where an unknown permission is loaded
and then subsequently logged, either via denial or auditallow. If a permission
set has some valid values mixed with unknown values, say `{ read write foo }`,
a check on `{ read write foo }` would fail to log the entire set.
To fix this, skip over the bad permissions/classes when expanding them to
strings. The unknowns should be logged during `selinux_set_mapping`, so
there is no need for further logging of the actual unknown permissions.
Signed-off-by: Mike Palmiotto <mike.palmiotto@xxxxxxxxxxxxxxx>
---
libselinux/src/stringrep.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/libselinux/src/stringrep.c b/libselinux/src/stringrep.c
index ad29f76d..85579422 100644
--- a/libselinux/src/stringrep.c
+++ b/libselinux/src/stringrep.c
@@ -276,19 +276,15 @@ int security_av_string(security_class_t tclass, access_vector_t av, char **res)
char *ptr;
/* first pass computes the required length */
- while (tmp) {
+ for (i = 0; tmp; tmp >>= 1, i++) {
Remove the redundant initialization in the declaration now that you are
doing it here (which is better, I agree).
if (tmp & 1) {
str = security_av_perm_to_string(tclass, av & (1<<i));
- if (str)
- len += strlen(str) + 1;
- else {
- rc = -1;
- errno = EINVAL;
- goto out;
+ if (!str) {
+ continue;
}
No need to bracket it when it is a single statement.
+
+ len += strlen(str) + 1;
Might be clearer as:
if (str)
len += strlen(str) + 1;
And just let it fall through to the end of the loop otherwise - no need
for explicit continue here.
}
- tmp >>= 1;
- i++;
}
*res = malloc(len);
@@ -298,7 +294,6 @@ int security_av_string(security_class_t tclass, access_vector_t av, char **res)
}
/* second pass constructs the string */
- i = 0;
tmp = av;
ptr = *res;
@@ -308,12 +303,13 @@ int security_av_string(security_class_t tclass, access_vector_t av, char **res)
}
ptr += sprintf(ptr, "{ ");
- while (tmp) {
- if (tmp & 1)
- ptr += sprintf(ptr, "%s ", security_av_perm_to_string(
- tclass, av & (1<<i)));
- tmp >>= 1;
- i++;
+ for (i = 0; tmp; tmp >>= 1, i++) {
+ if (tmp & 1) {
+ str = security_av_perm_to_string(tclass, av & (1<<i));
+ if (str) {
+ ptr += sprintf(ptr, "%s ", str);
+ }
No need for { } around a single statement.
+ }
}
sprintf(ptr, "}");
out:
