From b0c636b99997c8594da6a46e166ce4fcf6956fda Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Feb 2008 12:58:40 -0500 Subject: [PATCH] SELinux: create new open permission Adds a new open permission inside SELinux when 'opening' a file. The idea is that opening a file and reading/writing to that file are not the same thing. Its different if a program had its stdout redirected to /tmp/output than if the program tried to directly open /tmp/output. This should allow policy writers to more liberally give read/write permissions across the policy while still blocking many design and programing flaws SELinux is so good at catching today. Signed-off-by: Eric Paris Acked-by: Stephen Smalley Reviewed-by: Paul Moore Signed-off-by: James Morris --- security/selinux/hooks.c | 31 +++++++++++++++++++- security/selinux/include/av_perm_to_string.h | 5 ++++ security/selinux/include/av_permissions.h | 5 ++++ security/selinux/include/security.h | 2 ++ security/selinux/selinuxfs.c | 3 +- security/selinux/ss/services.c | 3 ++ 6 files changed, 47 insertions(+), 2 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 710894d4841..d569cde440e 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1615,6 +1615,35 @@ static inline u32 file_mask_to_av(int mode, int mask) return av; } +/* + * Convert a file mask to an access vector and include the correct open + * open permission. + */ +static inline u32 open_file_mask_to_av(int mode, int mask) +{ + u32 av = file_mask_to_av(mode, mask); + + if (selinux_policycap_openperm) { + /* + * lnk files and socks do not really have an 'open' + */ + if (S_ISREG(mode)) + av |= FILE__OPEN; + else if (S_ISCHR(mode)) + av |= CHR_FILE__OPEN; + else if (S_ISBLK(mode)) + av |= BLK_FILE__OPEN; + else if (S_ISFIFO(mode)) + av |= FIFO_FILE__OPEN; + else if (S_ISDIR(mode)) + av |= DIR__OPEN; + else + printk(KERN_ERR "SELinux: WARNING: inside open_file_to_av " + "with unknown mode:%x\n", mode); + } + return av; +} + /* Convert a Linux file to an access vector. */ static inline u32 file_to_av(struct file *file) { @@ -2532,7 +2561,7 @@ static int selinux_inode_permission(struct inode *inode, int mask, } return inode_has_perm(current, inode, - file_mask_to_av(inode->i_mode, mask), NULL); + open_file_mask_to_av(inode->i_mode, mask), NULL); } static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) diff --git a/security/selinux/include/av_perm_to_string.h b/security/selinux/include/av_perm_to_string.h index d5696690d3a..1223b4ff9be 100644 --- a/security/selinux/include/av_perm_to_string.h +++ b/security/selinux/include/av_perm_to_string.h @@ -14,12 +14,17 @@ S_(SECCLASS_DIR, DIR__REPARENT, "reparent") S_(SECCLASS_DIR, DIR__SEARCH, "search") S_(SECCLASS_DIR, DIR__RMDIR, "rmdir") + S_(SECCLASS_DIR, DIR__OPEN, "open") S_(SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, "execute_no_trans") S_(SECCLASS_FILE, FILE__ENTRYPOINT, "entrypoint") S_(SECCLASS_FILE, FILE__EXECMOD, "execmod") + S_(SECCLASS_FILE, FILE__OPEN, "open") S_(SECCLASS_CHR_FILE, CHR_FILE__EXECUTE_NO_TRANS, "execute_no_trans") S_(SECCLASS_CHR_FILE, CHR_FILE__ENTRYPOINT, "entrypoint") S_(SECCLASS_CHR_FILE, CHR_FILE__EXECMOD, "execmod") + S_(SECCLASS_CHR_FILE, CHR_FILE__OPEN, "open") + S_(SECCLASS_BLK_FILE, BLK_FILE__OPEN, "open") + S_(SECCLASS_FIFO_FILE, FIFO_FILE__OPEN, "open") S_(SECCLASS_FD, FD__USE, "use") S_(SECCLASS_TCP_SOCKET, TCP_SOCKET__CONNECTTO, "connectto") S_(SECCLASS_TCP_SOCKET, TCP_SOCKET__NEWCONN, "newconn") diff --git a/security/selinux/include/av_permissions.h b/security/selinux/include/av_permissions.h index 75b41311ab8..c4c51165c50 100644 --- a/security/selinux/include/av_permissions.h +++ b/security/selinux/include/av_permissions.h @@ -79,6 +79,7 @@ #define DIR__REPARENT 0x00080000UL #define DIR__SEARCH 0x00100000UL #define DIR__RMDIR 0x00200000UL +#define DIR__OPEN 0x00400000UL #define FILE__IOCTL 0x00000001UL #define FILE__READ 0x00000002UL #define FILE__WRITE 0x00000004UL @@ -99,6 +100,7 @@ #define FILE__EXECUTE_NO_TRANS 0x00020000UL #define FILE__ENTRYPOINT 0x00040000UL #define FILE__EXECMOD 0x00080000UL +#define FILE__OPEN 0x00100000UL #define LNK_FILE__IOCTL 0x00000001UL #define LNK_FILE__READ 0x00000002UL #define LNK_FILE__WRITE 0x00000004UL @@ -136,6 +138,7 @@ #define CHR_FILE__EXECUTE_NO_TRANS 0x00020000UL #define CHR_FILE__ENTRYPOINT 0x00040000UL #define CHR_FILE__EXECMOD 0x00080000UL +#define CHR_FILE__OPEN 0x00100000UL #define BLK_FILE__IOCTL 0x00000001UL #define BLK_FILE__READ 0x00000002UL #define BLK_FILE__WRITE 0x00000004UL @@ -153,6 +156,7 @@ #define BLK_FILE__SWAPON 0x00004000UL #define BLK_FILE__QUOTAON 0x00008000UL #define BLK_FILE__MOUNTON 0x00010000UL +#define BLK_FILE__OPEN 0x00020000UL #define SOCK_FILE__IOCTL 0x00000001UL #define SOCK_FILE__READ 0x00000002UL #define SOCK_FILE__WRITE 0x00000004UL @@ -187,6 +191,7 @@ #define FIFO_FILE__SWAPON 0x00004000UL #define FIFO_FILE__QUOTAON 0x00008000UL #define FIFO_FILE__MOUNTON 0x00010000UL +#define FIFO_FILE__OPEN 0x00020000UL #define FD__USE 0x00000001UL #define SOCKET__IOCTL 0x00000001UL #define SOCKET__READ 0x00000002UL diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 44e12ec8809..315b4ec1e12 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -48,11 +48,13 @@ extern int selinux_mls_enabled; /* Policy capabilities */ enum { POLICYDB_CAPABILITY_NETPEER, + POLICYDB_CAPABILITY_OPENPERM, __POLICYDB_CAPABILITY_MAX }; #define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1) extern int selinux_policycap_netpeer; +extern int selinux_policycap_openperm; int security_load_policy(void * data, size_t len); diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 0341567665b..1d996bb953b 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -42,7 +42,8 @@ /* Policy capability filenames */ static char *policycap_names[] = { - "network_peer_controls" + "network_peer_controls", + "open_perms" }; unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 26de2be0c8e..4a14348de87 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -61,6 +61,7 @@ extern void selnl_notify_policyload(u32 seqno); unsigned int policydb_loaded_version; int selinux_policycap_netpeer; +int selinux_policycap_openperm; /* * This is declared in avc.c @@ -1308,6 +1309,8 @@ static void security_load_policycaps(void) { selinux_policycap_netpeer = ebitmap_get_bit(&policydb.policycaps, POLICYDB_CAPABILITY_NETPEER); + selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps, + POLICYDB_CAPABILITY_OPENPERM); } extern void selinux_complete_init(void); -- 2.20.1