From 9a59daa03df72526d234b91dd3e32ded5aebd3ef Mon Sep 17 00:00:00 2001 From: Stephen Smalley Date: Wed, 14 May 2008 10:33:55 -0400 Subject: SELinux: fix sleeping allocation in security_context_to_sid 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 Signed-off-by: James Morris --- security/selinux/ss/services.c | 70 ++++++++++++++++++++++++------------------ 1 file changed, 40 insertions(+), 30 deletions(-) (limited to 'security') diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index b86ac9da6cf3..2d5e5a3a8aa9 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -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", -- cgit v1.2.3-59-g8ed1b