On Thu, 17 Feb 2022 at 14:14, Vit Mojzis <vmojzis@xxxxxxxxxx> wrote:
>
> Spaces before values in /etc/selinux/config should be ignored just as
> spaces after them are.
>
> E.g. "SELINUXTYPE= targeted" should be a valid value.
>
> Fixes:
> # sed -i 's/^SELINUXTYPE=/SELINUXTYPE= /g' /etc/selinux/config
> # dnf install <any_package>
> ...
> RPM: error: selabel_open: (/etc/selinux/ targeted/contexts/files/file_contexts) No such file or directory
> RPM: error: Plugin selinux: hook tsm_pre failed
> ...
> Error: Could not run transaction.
>
> Signed-off-by: Vit Mojzis <vmojzis@xxxxxxxxxx>
> ---
>
> Sorry for the delay. I sent the fixed patch to a wrong mailing list.
>
> libselinux/src/selinux_config.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/libselinux/src/selinux_config.c b/libselinux/src/selinux_config.c
> index 97f81a8b..d2e49ee1 100644
> --- a/libselinux/src/selinux_config.c
> +++ b/libselinux/src/selinux_config.c
> @@ -92,6 +92,7 @@ int selinux_getenforcemode(int *enforce)
> FILE *cfg = fopen(SELINUXCONFIG, "re");
> if (cfg) {
> char *buf;
> + char *tag;
> int len = sizeof(SELINUXTAG) - 1;
> buf = malloc(selinux_page_size);
> if (!buf) {
> @@ -101,21 +102,24 @@ int selinux_getenforcemode(int *enforce)
> while (fgets_unlocked(buf, selinux_page_size, cfg)) {
> if (strncmp(buf, SELINUXTAG, len))
> continue;
> + tag = buf+len;
> + while (isspace(*tag))
> + tag++;
> if (!strncasecmp
> - (buf + len, "enforcing", sizeof("enforcing") - 1)) {
> + (tag, "enforcing", sizeof("enforcing") - 1)) {
> *enforce = 1;
> ret = 0;
> break;
> } else
> if (!strncasecmp
> - (buf + len, "permissive",
> + (tag, "permissive",
> sizeof("permissive") - 1)) {
> *enforce = 0;
> ret = 0;
> break;
> } else
> if (!strncasecmp
> - (buf + len, "disabled",
> + (tag, "disabled",
> sizeof("disabled") - 1)) {
> *enforce = -1;
> ret = 0;
> @@ -176,7 +180,10 @@ static void init_selinux_config(void)
>
> if (!strncasecmp(buf_p, SELINUXTYPETAG,
> sizeof(SELINUXTYPETAG) - 1)) {
> - type = strdup(buf_p + sizeof(SELINUXTYPETAG) - 1);
> + buf_p += sizeof(SELINUXTYPETAG) - 1;
> + while (isspace(*buf_p))
Strictly speaking one should cast to unsigned char to avoid UB, see
[1], but that
seems to be not done in SElinux userspace as
grep -REw "(isalnum|isalpha|isascii|isblank|iscntrl|isdigit|isgraph|islower|isprint|ispunct|isspace|isupper|isxdigit|toascii|toupper|tolower)"
shows 87 usages.
[1]: https://wiki.sei.cmu.edu/confluence/display/c/STR37-C.+Arguments+to+character-handling+functions+must+be+representable+as+an+unsigned+char
> + buf_p++;
> + type = strdup(buf_p);
> if (!type) {
> free(line_buf);
> fclose(fp);
> @@ -199,6 +206,8 @@ static void init_selinux_config(void)
> } else if (!strncmp(buf_p, REQUIRESEUSERS,
> sizeof(REQUIRESEUSERS) - 1)) {
> value = buf_p + sizeof(REQUIRESEUSERS) - 1;
> + while (isspace(*value))
> + value++;
> intptr = &require_seusers;
> } else {
> continue;
> --
> 2.30.2
>
