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smack: rewrite smack_sb_eat_lsm_opts()

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make it use smack_add_opt() and avoid separate copies - gather
non-LSM options by memmove() in place

Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2018-12-16 01:37:06 -05:00
parent c3300aaf95
commit d2497e12e2
1 changed files with 23 additions and 85 deletions
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92
security/smack/smack_lsm.c
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@ -599,53 +599,6 @@ static void smack_free_mnt_opts(void *mnt_opts)
kfree(opts); kfree(opts);
} }
/**
* smack_sb_copy_data - copy mount options data for processing
* @orig: where to start
* @smackopts: mount options string
*
* Returns 0 on success or -ENOMEM on error.
*
* Copy the Smack specific mount options out of the mount
* options list.
*/
static int smack_sb_copy_data(char *orig, char *smackopts)
{
char *cp, *commap, *otheropts, *dp;
otheropts = (char *)get_zeroed_page(GFP_KERNEL);
if (otheropts == NULL)
return -ENOMEM;
for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) {
if (strstr(cp, SMK_FSDEFAULT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSFLOOR) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSHAT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSROOT) == cp)
dp = smackopts;
else if (strstr(cp, SMK_FSTRANS) == cp)
dp = smackopts;
else
dp = otheropts;
commap = strchr(cp, ',');
if (commap != NULL)
*commap = '\0';
if (*dp != '\0')
strcat(dp, ",");
strcat(dp, cp);
}
strcpy(orig, otheropts);
free_page((unsigned long)otheropts);
return 0;
}
static int smack_add_opt(int token, const char *s, void **mnt_opts) static int smack_add_opt(int token, const char *s, void **mnt_opts)
{ {
struct smack_mnt_opts *opts = *mnt_opts; struct smack_mnt_opts *opts = *mnt_opts;
@ -656,7 +609,6 @@ static int smack_add_opt(int token, const char *s, void **mnt_opts)
return -ENOMEM; return -ENOMEM;
*mnt_opts = opts; *mnt_opts = opts;
} }
if (!s) if (!s)
return -ENOMEM; return -ENOMEM;
@ -694,22 +646,10 @@ out_opt_err:
return -EINVAL; return -EINVAL;
} }
/** static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
* smack_parse_opts_str - parse Smack specific mount options
* @options: mount options string
* @opts: where to store converted mount opts
*
* Returns 0 on success or -ENOMEM on error.
*
* converts Smack specific mount options to generic security option format
*/
static int smack_parse_opts_str(char *options,
void **mnt_opts)
{ {
char *from = options; char *from = options, *to = options;
bool first = true;
if (!options)
return 0;
while (1) { while (1) {
char *next = strchr(from, ','); char *next = strchr(from, ',');
@ -722,6 +662,7 @@ static int smack_parse_opts_str(char *options,
len = strlen(from); len = strlen(from);
token = match_opt_prefix(from, len, &arg); token = match_opt_prefix(from, len, &arg);
if (token != Opt_error) {
arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL); arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
rc = smack_add_opt(token, arg, mnt_opts); rc = smack_add_opt(token, arg, mnt_opts);
if (unlikely(rc)) { if (unlikely(rc)) {
@ -731,27 +672,24 @@ static int smack_parse_opts_str(char *options,
*mnt_opts = NULL; *mnt_opts = NULL;
return rc; return rc;
} }
} else {
if (!first) { // copy with preceding comma
from--;
len++;
}
if (to != from)
memmove(to, from, len);
to += len;
first = false;
}
if (!from[len]) if (!from[len])
break; break;
from += len + 1; from += len + 1;
} }
*to = '\0';
return 0; return 0;
} }
static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
char *s = (char *)get_zeroed_page(GFP_KERNEL);
int err;
if (!s)
return -ENOMEM;
err = smack_sb_copy_data(options, s);
if (!err)
err = smack_parse_opts_str(s, mnt_opts);
free_page((unsigned long)s);
return err;
}
/** /**
* smack_set_mnt_opts - set Smack specific mount options * smack_set_mnt_opts - set Smack specific mount options
* @sb: the file system superblock * @sb: the file system superblock