From 01c2253a0fbdccb58cd79d4ff9ab39964bfb4474 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Mon, 16 Dec 2024 17:40:07 +0100
Subject: [PATCH] selinux: make more use of str_read() when loading the policy
MIME-Version: 1.0
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Simplify the call sites, and enable future string validation in a single
place.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
---
security/selinux/ss/conditional.c | 10 ++--------
security/selinux/ss/policydb.c | 22 ++++++++--------------
security/selinux/ss/policydb.h | 2 ++
3 files changed, 12 insertions(+), 22 deletions(-)
diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index d8dcaf2ca88f6..1bebfcb9c6a12 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -230,17 +230,11 @@ int cond_read_bool(struct policydb *p, struct symtab *s, struct policy_file *fp)
goto err;
len = le32_to_cpu(buf[2]);
- if (((len == 0) || (len == (u32)-1)))
- goto err;
- rc = -ENOMEM;
- key = kmalloc(len + 1, GFP_KERNEL);
- if (!key)
- goto err;
- rc = next_entry(key, fp, len);
+ rc = str_read(&key, GFP_KERNEL, fp, len);
if (rc)
goto err;
- key[len] = '\0';
+
rc = symtab_insert(s, key, booldatum);
if (rc)
goto err;
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 0850ea6ae0185..9ea9719437136 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1093,7 +1093,7 @@ static int context_read_and_validate(struct context *c, struct policydb *p,
* binary representation file.
*/
-static int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len)
+int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len)
{
int rc;
char *str;
@@ -2473,24 +2473,18 @@ int policydb_read(struct policydb *p, struct policy_file *fp)
goto bad;
}
- rc = -ENOMEM;
- policydb_str = kmalloc(len + 1, GFP_KERNEL);
- if (!policydb_str) {
- pr_err("SELinux: unable to allocate memory for policydb "
- "string of length %d\n",
- len);
- goto bad;
- }
-
- rc = next_entry(policydb_str, fp, len);
+ rc = str_read(&policydb_str, GFP_KERNEL, fp, len);
if (rc) {
- pr_err("SELinux: truncated policydb string identifier\n");
- kfree(policydb_str);
+ if (rc == -ENOMEM) {
+ pr_err("SELinux: unable to allocate memory for policydb string of length %d\n",
+ len);
+ } else {
+ pr_err("SELinux: truncated policydb string identifier\n");
+ }
goto bad;
}
rc = -EINVAL;
- policydb_str[len] = '\0';
if (strcmp(policydb_str, POLICYDB_STRING)) {
pr_err("SELinux: policydb string %s does not match "
"my string %s\n",
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 80d1fa7e49954..25650224b6e7c 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -386,6 +386,8 @@ static inline char *sym_name(struct policydb *p, unsigned int sym_num,
return p->sym_val_to_name[sym_num][element_nr];
}
+extern int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len);
+
extern u16 string_to_security_class(struct policydb *p, const char *name);
extern u32 string_to_av_perm(struct policydb *p, u16 tclass, const char *name);
--
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