From 44d37ad3602b3823764eeb0f6c1ee3ef6c4fb936 Mon Sep 17 00:00:00 2001 From: Jeff Vander Stoep Date: Wed, 21 Oct 2015 17:44:25 -0400 Subject: selinux: do not check open perm on ftruncate call Use the ATTR_FILE attribute to distinguish between truncate() and ftruncate() system calls. The two other cases where do_truncate is called with a filp (and therefore ATTR_FILE is set) are for coredump files and for open(O_TRUNC). In both of those cases the open permission has already been checked during file open and therefore does not need to be repeated. Commit 95dbf739313f ("SELinux: check OPEN on truncate calls") fixed a major issue where domains were allowed to truncate files without the open permission. However, it introduced a new bug where a domain with the write permission can no longer ftruncate files without the open permission, even when they receive an already open file. Signed-off-by: Jeff Vander Stoep Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e4369d86e588..7cd71cea0503 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2946,7 +2946,8 @@ static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) return dentry_has_perm(cred, dentry, FILE__SETATTR); - if (selinux_policycap_openperm && (ia_valid & ATTR_SIZE)) + if (selinux_policycap_openperm && (ia_valid & ATTR_SIZE) + && !(ia_valid & ATTR_FILE)) av |= FILE__OPEN; return dentry_has_perm(cred, dentry, av); -- cgit v1.2.3 From 44be2f65d979291ffb2a47112449507ffe1f9726 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 21 Oct 2015 17:44:25 -0400 Subject: selinux: introduce security_context_str_to_sid There seems to be a little confusion as to whether the scontext_len parameter of security_context_to_sid() includes the nul-byte or not. Reading security_context_to_sid_core(), it seems that the expectation is that it does not (both the string copying and the test for scontext_len being zero hint at that). Introduce the helper security_context_str_to_sid() to do the strlen() call and fix all callers. Signed-off-by: Rasmus Villemoes Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 12 ++++-------- security/selinux/include/security.h | 2 ++ security/selinux/selinuxfs.c | 26 +++++++++----------------- security/selinux/ss/services.c | 5 +++++ 4 files changed, 20 insertions(+), 25 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 7cd71cea0503..9ed1b5dbcb39 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -674,10 +674,9 @@ static int selinux_set_mnt_opts(struct super_block *sb, if (flags[i] == SBLABEL_MNT) continue; - rc = security_context_to_sid(mount_options[i], - strlen(mount_options[i]), &sid, GFP_KERNEL); + rc = security_context_str_to_sid(mount_options[i], &sid, GFP_KERNEL); if (rc) { - printk(KERN_WARNING "SELinux: security_context_to_sid" + printk(KERN_WARNING "SELinux: security_context_str_to_sid" "(%s) failed for (dev %s, type %s) errno=%d\n", mount_options[i], sb->s_id, name, rc); goto out; @@ -2617,15 +2616,12 @@ static int selinux_sb_remount(struct super_block *sb, void *data) for (i = 0; i < opts.num_mnt_opts; i++) { u32 sid; - size_t len; if (flags[i] == SBLABEL_MNT) continue; - len = strlen(mount_options[i]); - rc = security_context_to_sid(mount_options[i], len, &sid, - GFP_KERNEL); + rc = security_context_str_to_sid(mount_options[i], &sid, GFP_KERNEL); if (rc) { - printk(KERN_WARNING "SELinux: security_context_to_sid" + printk(KERN_WARNING "SELinux: security_context_str_to_sid" "(%s) failed for (dev %s, type %s) errno=%d\n", mount_options[i], sb->s_id, sb->s_type->name, rc); goto out_free_opts; diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 6a681d26bf20..223e9fd15d66 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -166,6 +166,8 @@ int security_sid_to_context_force(u32 sid, char **scontext, u32 *scontext_len); int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *out_sid, gfp_t gfp); +int security_context_str_to_sid(const char *scontext, u32 *out_sid, gfp_t gfp); + int security_context_to_sid_default(const char *scontext, u32 scontext_len, u32 *out_sid, u32 def_sid, gfp_t gfp_flags); diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 5bed7716f8ab..c02da25d7b63 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -731,13 +731,11 @@ static ssize_t sel_write_access(struct file *file, char *buf, size_t size) if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3) goto out; - length = security_context_to_sid(scon, strlen(scon) + 1, &ssid, - GFP_KERNEL); + length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL); if (length) goto out; - length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid, - GFP_KERNEL); + length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL); if (length) goto out; @@ -819,13 +817,11 @@ static ssize_t sel_write_create(struct file *file, char *buf, size_t size) objname = namebuf; } - length = security_context_to_sid(scon, strlen(scon) + 1, &ssid, - GFP_KERNEL); + length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL); if (length) goto out; - length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid, - GFP_KERNEL); + length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL); if (length) goto out; @@ -882,13 +878,11 @@ static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size) if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3) goto out; - length = security_context_to_sid(scon, strlen(scon) + 1, &ssid, - GFP_KERNEL); + length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL); if (length) goto out; - length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid, - GFP_KERNEL); + length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL); if (length) goto out; @@ -940,7 +934,7 @@ static ssize_t sel_write_user(struct file *file, char *buf, size_t size) if (sscanf(buf, "%s %s", con, user) != 2) goto out; - length = security_context_to_sid(con, strlen(con) + 1, &sid, GFP_KERNEL); + length = security_context_str_to_sid(con, &sid, GFP_KERNEL); if (length) goto out; @@ -1000,13 +994,11 @@ static ssize_t sel_write_member(struct file *file, char *buf, size_t size) if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3) goto out; - length = security_context_to_sid(scon, strlen(scon) + 1, &ssid, - GFP_KERNEL); + length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL); if (length) goto out; - length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid, - GFP_KERNEL); + length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL); if (length) goto out; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index b7df12ba61d8..c550df0e0ff1 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -1476,6 +1476,11 @@ int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid, sid, SECSID_NULL, gfp, 0); } +int security_context_str_to_sid(const char *scontext, u32 *sid, gfp_t gfp) +{ + return security_context_to_sid(scontext, strlen(scontext), sid, gfp); +} + /** * security_context_to_sid_default - Obtain a SID for a given security context, * falling back to specified default if needed. -- cgit v1.2.3 From 20ba96aeebd40f09a1d626913235941e290992c7 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Wed, 21 Oct 2015 17:44:26 -0400 Subject: selinux: remove pointless cast in selinux_inode_setsecurity() security_context_to_sid() expects a const char* argument, so there's no point in casting away the const qualifier of value. Signed-off-by: Rasmus Villemoes Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9ed1b5dbcb39..1530f661ef85 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3163,7 +3163,7 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name, if (!value || !size) return -EACCES; - rc = security_context_to_sid((void *)value, size, &newsid, GFP_KERNEL); + rc = security_context_to_sid(value, size, &newsid, GFP_KERNEL); if (rc) return rc; -- cgit v1.2.3 From 1d2a168a085f1c65b895f258ee11a52813d25af6 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Wed, 21 Oct 2015 17:44:27 -0400 Subject: selinux: ioctl_has_perm should be static Fixes the following sparse warning: security/selinux/hooks.c:3242:5: warning: symbol 'ioctl_has_perm' was not declared. Should it be static? Signed-off-by: Geliang Tang Acked-by: Jeff Vander Stoep Acked-by: Stephen Smalley Signed-off-by: Paul Moore --- security/selinux/hooks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 1530f661ef85..799d15aa35f9 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3235,7 +3235,7 @@ static void selinux_file_free_security(struct file *file) * Check whether a task has the ioctl permission and cmd * operation to an inode. */ -int ioctl_has_perm(const struct cred *cred, struct file *file, +static int ioctl_has_perm(const struct cred *cred, struct file *file, u32 requested, u16 cmd) { struct common_audit_data ad; -- cgit v1.2.3 From 63205654c0e05e5ffa1c6eef2fbef21dcabd2185 Mon Sep 17 00:00:00 2001 From: Sangwoo Date: Wed, 21 Oct 2015 17:44:30 -0400 Subject: selinux: Use a kmem_cache for allocation struct file_security_struct The size of struct file_security_struct is 16byte at my setup. But, the real allocation size for per each file_security_struct is 64bytes in my setup that kmalloc min size is 64bytes because ARCH_DMA_MINALIGN is 64. This allocation is called every times at file allocation(alloc_file()). So, the total slack memory size(allocated size - request size) is increased exponentially. E.g) Min Kmalloc Size : 64bytes, Unit : bytes Allocated Size | Request Size | Slack Size | Allocation Count --------------------------------------------------------------- 770048 | 192512 | 577536 | 12032 At the result, this change reduce memory usage 42bytes per each file_security_struct Signed-off-by: Sangwoo Acked-by: Stephen Smalley [PM: removed extra subject prefix] Signed-off-by: Paul Moore --- security/selinux/hooks.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 799d15aa35f9..305399225010 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -126,6 +126,7 @@ int selinux_enabled = 1; #endif static struct kmem_cache *sel_inode_cache; +static struct kmem_cache *file_security_cache; /** * selinux_secmark_enabled - Check to see if SECMARK is currently enabled @@ -287,7 +288,7 @@ static int file_alloc_security(struct file *file) struct file_security_struct *fsec; u32 sid = current_sid(); - fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL); + fsec = kmem_cache_zalloc(file_security_cache, GFP_KERNEL); if (!fsec) return -ENOMEM; @@ -302,7 +303,7 @@ static void file_free_security(struct file *file) { struct file_security_struct *fsec = file->f_security; file->f_security = NULL; - kfree(fsec); + kmem_cache_free(file_security_cache, fsec); } static int superblock_alloc_security(struct super_block *sb) @@ -6086,6 +6087,9 @@ static __init int selinux_init(void) sel_inode_cache = kmem_cache_create("selinux_inode_security", sizeof(struct inode_security_struct), 0, SLAB_PANIC, NULL); + file_security_cache = kmem_cache_create("selinux_file_security", + sizeof(struct file_security_struct), + 0, SLAB_PANIC, NULL); avc_init(); security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks)); -- cgit v1.2.3