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SELinux: fix sleeping allocation in security_context_to_sid

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Fix a sleeping function called from invalid context bug by moving allocation
to the callers prior to taking the policy rdlock.

Signed-off-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Stephen Smalley 2008-05-14 10:33:55 -04:00 committed by James Morris
parent 12b29f3455
commit 9a59daa03d
1 changed files with 40 additions and 30 deletions
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70
security/selinux/ss/services.c
View file

@ -730,15 +730,16 @@ int security_sid_to_context_force(u32 sid, char **scontext, u32 *scontext_len)
return security_sid_to_context_core(sid, scontext, scontext_len, 1);
}
/*
* Caveat: Mutates scontext.
*/
static int string_to_context_struct(struct policydb *pol,
struct sidtab *sidtabp,
const char *scontext,
char *scontext,
u32 scontext_len,
struct context *ctx,
u32 def_sid,
gfp_t gfp_flags)
u32 def_sid)
{
char *scontext2 = NULL;
struct role_datum *role;
struct type_datum *typdatum;
struct user_datum *usrdatum;
@ -747,19 +748,10 @@ static int string_to_context_struct(struct policydb *pol,
context_init(ctx);
/* Copy the string so that we can modify the copy as we parse it. */
scontext2 = kmalloc(scontext_len+1, gfp_flags);
if (!scontext2) {
rc = -ENOMEM;
goto out;
}
memcpy(scontext2, scontext, scontext_len);
scontext2[scontext_len] = 0;
/* Parse the security context. */
rc = -EINVAL;
scontextp = (char *) scontext2;
scontextp = (char *) scontext;
/* Extract the user. */
p = scontextp;
@ -809,7 +801,7 @@ static int string_to_context_struct(struct policydb *pol,
if (rc)
goto out;
if ((p - scontext2) < scontext_len) {
if ((p - scontext) < scontext_len) {
rc = -EINVAL;
goto out;
}
@ -822,7 +814,6 @@ static int string_to_context_struct(struct policydb *pol,
}
rc = 0;
out:
kfree(scontext2);
return rc;
}
@ -830,6 +821,7 @@ static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
u32 *sid, u32 def_sid, gfp_t gfp_flags,
int force)
{
char *scontext2, *str = NULL;
struct context context;
int rc = 0;
@ -839,27 +831,38 @@ static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
for (i = 1; i < SECINITSID_NUM; i++) {
if (!strcmp(initial_sid_to_string[i], scontext)) {
*sid = i;
goto out;
return 0;
}
}
*sid = SECINITSID_KERNEL;
goto out;
return 0;
}
*sid = SECSID_NULL;
/* Copy the string so that we can modify the copy as we parse it. */
scontext2 = kmalloc(scontext_len+1, gfp_flags);
if (!scontext2)
return -ENOMEM;
memcpy(scontext2, scontext, scontext_len);
scontext2[scontext_len] = 0;
if (force) {
/* Save another copy for storing in uninterpreted form */
str = kstrdup(scontext2, gfp_flags);
if (!str) {
kfree(scontext2);
return -ENOMEM;
}
}
POLICY_RDLOCK;
rc = string_to_context_struct(&policydb, &sidtab,
scontext, scontext_len,
&context, def_sid, gfp_flags);
scontext2, scontext_len,
&context, def_sid);
if (rc == -EINVAL && force) {
context.str = kmalloc(scontext_len+1, gfp_flags);
if (!context.str) {
rc = -ENOMEM;
goto out;
}
memcpy(context.str, scontext, scontext_len);
context.str[scontext_len] = 0;
context.str = str;
context.len = scontext_len;
str = NULL;
} else if (rc)
goto out;
rc = sidtab_context_to_sid(&sidtab, &context, sid);
@ -867,6 +870,8 @@ static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
context_destroy(&context);
out:
POLICY_RDUNLOCK;
kfree(scontext2);
kfree(str);
return rc;
}
@ -1339,9 +1344,14 @@ static int convert_context(u32 key,
if (c->str) {
struct context ctx;
rc = string_to_context_struct(args->newp, NULL, c->str,
c->len, &ctx, SECSID_NULL,
GFP_KERNEL);
s = kstrdup(c->str, GFP_KERNEL);
if (!s) {
rc = -ENOMEM;
goto out;
}
rc = string_to_context_struct(args->newp, NULL, s,
c->len, &ctx, SECSID_NULL);
kfree(s);
if (!rc) {
printk(KERN_INFO
"SELinux: Context %s became valid (mapped).\n",