Re: PATCH: libselinux matchpathcon() eliminate %as scanf format
Todd C. Miller wrote:
> This is a patch I sent in last year but forgot to split up as
> requested; it still applies to the recently-released selinux-1.34.0.
>
> THe patch replaces usage of the non-standard %as scanf() format
> (which conflicts with C99) with strtok_r(). This does mean that
> line_buf is modified but this variable is only used as an argument
> to process_line() and is freed thereafter.
>
> I made this change as part of the port of libselinux to SEBSD and
> SEDarwin.
>
> - todd
Acked-by: Karl MacMillan <kmacmillan@...>
I made a few updates for style (the !! thing was too clever for me) and
merged into trunk and stable. Actual merged version is attached.
> --- matchpathcon.c 2007-01-25 14:19:39.000000000 -0500
> +++ matchpathcon.c 2007-01-25 14:21:32.000000000 -0500
> <at> <at> -444,7 +444,7 <at> <at>
> int pass, unsigned lineno)
> {
> int items, len, regerr, ret;
> - char *buf_p;
> + char *buf_p, *ptr;
> char *regex, *type, *context;
> const char *reg_buf;
> char *anchored_regex;
> <at> <at> -459,7 +459,11 <at> <at>
> /* Skip comment lines and empty lines. */
> if (*buf_p == '#' || *buf_p == 0)
> return 0;
> - items = sscanf(line_buf, "%as %as %as", ®ex, &type, &context);
> +
> + regex = strtok_r(buf_p, " \t", &ptr);
> + type = strtok_r(NULL, " \t", &ptr);
> + context = strtok_r(NULL, " \t", &ptr);
> + items = !!regex + !!type + !!context;
> if (items < 2) {
> myprintf("%s: line %d is missing fields, skipping\n", path,
> lineno);
> <at> <at> -470,6 +474,15 <at> <at>
> type = NULL;
> }
>
> + regex = strdup(regex);
> + if (type != NULL)
> + type = strdup(type);
> + context = strdup(context);
> + if (!!regex + !!type + !!context != items) {
> + ret = -1;
> + goto finish;
> + }
> +
> reg_buf = regex;
> len = get_stem_from_spec(reg_buf);
> if (len && prefix && strncmp(prefix, regex, len)) {
>
> --
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Index: libselinux/src/matchpathcon.c
===================================================================
--- libselinux/src/matchpathcon.c (revision 2209)
+++ libselinux/src/matchpathcon.c (working copy)
<at> <at> -444,7 +444,7 <at> <at>
int pass, unsigned lineno)
{
int items, len, regerr, ret;
- char *buf_p;
+ char *buf_p, *ptr;
char *regex, *type, *context;
const char *reg_buf;
char *anchored_regex;
<at> <at> -459,7 +459,18 <at> <at>
/* Skip comment lines and empty lines. */
if (*buf_p == '#' || *buf_p == 0)
return 0;
- items = sscanf(line_buf, "%as %as %as", ®ex, &type, &context);
+
+ items = 0;
+ regex = strtok_r(buf_p, " \t", &ptr);
+ if (regex)
+ items += 1;
+ type = strtok_r(NULL, " \t", &ptr);
+ if (type)
+ items += 1;
+ context = strtok_r(NULL, " \t", &ptr);
+ if (context)
+ items += 1;
+
if (items < 2) {
myprintf("%s: line %d is missing fields, skipping\n", path,
lineno);
<at> <at> -470,6 +481,23 <at> <at>
type = NULL;
}
+ regex = strdup(regex);
+ if (!regex) {
+ return -1;
+ }
+ if (type) {
+ type = strdup(type);
+ if (!type) {
+ ret = -1;
+ goto finish;
+ }
+ }
+ context = strdup(context);
+ if (!context) {
+ ret = -1;
+ goto finish;
+ }
+
reg_buf = regex;
len = get_stem_from_spec(reg_buf);
if (len && prefix && strncmp(prefix, regex, len)) {
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