On Mon, Jul 29, 2013 at 02:24:15AM -0700, Tyler Hicks wrote: > Add an interface for trusted applications to use when they need to query > AppArmor kernel policy to determine if an action should be allowed. > > This is a simplified interface that tries to make it as easy as possible > for applications to use. They provide a permissions mask and query > string and they get a pair of booleans back that let them know if the > action should be allowed and/or audited. > > Signed-off-by: Tyler Hicks <[email protected]>
Acked-by: Seth Arnold <[email protected]> with a few comments inline... > --- > libraries/libapparmor/src/Makefile.am | 2 +- > libraries/libapparmor/src/apparmor.h | 41 +++++++++++ > libraries/libapparmor/src/kernel_interface.c | 98 > +++++++++++++++++++++++++++ > libraries/libapparmor/src/libapparmor.map | 7 ++ > libraries/libapparmor/swig/SWIG/libapparmor.i | 2 + > 5 files changed, 149 insertions(+), 1 deletion(-) > > diff --git a/libraries/libapparmor/src/Makefile.am > b/libraries/libapparmor/src/Makefile.am > index 6507673..48bf2f4 100644 > --- a/libraries/libapparmor/src/Makefile.am > +++ b/libraries/libapparmor/src/Makefile.am > @@ -47,7 +47,7 @@ lib_LTLIBRARIES = libapparmor.la > noinst_HEADERS = grammar.h parser.h scanner.h af_protos.h > > libapparmor_la_SOURCES = grammar.y libaalogparse.c kernel_interface.c > scanner.c > -libapparmor_la_LDFLAGS = -version-info > $(AA_LIB_CURRENT):$(AA_LIB_REVISION):$(AA_LIB_AGE) -XCClinker -dynamic \ > +libapparmor_la_LDFLAGS = -version-info > $(AA_LIB_CURRENT):$(AA_LIB_REVISION):$(AA_LIB_AGE) -XCClinker -dynamic > -pthread \ > -Wl,--version-script=$(top_srcdir)/src/libapparmor.map > -Wl,-soname=libapparmor.so.1 > > pkgconfigdir = $(libdir)/pkgconfig > diff --git a/libraries/libapparmor/src/apparmor.h > b/libraries/libapparmor/src/apparmor.h > index 79bc69c..387e197 100644 > --- a/libraries/libapparmor/src/apparmor.h > +++ b/libraries/libapparmor/src/apparmor.h > @@ -18,10 +18,41 @@ > #ifndef _SYS_APPARMOR_H_ > #define _SYS_APPARMOR_H 1 > > +#include <stdint.h> > #include <sys/types.h> > > __BEGIN_DECLS > > +/* > + * Class of mediation types in the AppArmor policy db > + */ > +#define AA_CLASS_COND 0 > +#define AA_CLASS_UNKNOWN 1 > +#define AA_CLASS_FILE 2 > +#define AA_CLASS_CAP 3 > +#define AA_CLASS_NET 4 > +#define AA_CLASS_RLIMITS 5 > +#define AA_CLASS_DOMAIN 6 > +#define AA_CLASS_MOUNT 7 > +#define AA_CLASS_NS_DOMAIN 8 > +#define AA_CLASS_PTRACE 9 > + > +#define AA_CLASS_ENV 16 > + > +#define AA_CLASS_DBUS 32 > +#define AA_CLASS_X 33 > + > + > +/* Permission Flags for Mediation classes */ > +#define AA_MAY_WRITE (1 << 1) > +#define AA_MAY_READ (1 << 2) > +#define AA_MAY_BIND (1 << 6) > + > +#define AA_DBUS_SEND AA_MAY_WRITE > +#define AA_DBUS_RECEIVE AA_MAY_READ > +#define AA_DBUS_BIND AA_MAY_BIND > + > + > /* Prototypes for apparmor state queries */ > extern int aa_is_enabled(void); > extern int aa_find_mountpoint(char **mnt); > @@ -51,6 +82,16 @@ extern int aa_getcon(char **con, char **mode); > extern int aa_getpeercon_raw(int fd, char *buf, int *len, char **mode); > extern int aa_getpeercon(int fd, char **con, char **mode); > > +/* A NUL character is used to separate the query command prefix string from > the > + * rest of the query string. The query command sizes intentionally include > the > + * NUL-terminator in their values. > + */ > +#define AA_QUERY_CMD_LABEL "label" > +#define AA_QUERY_CMD_LABEL_SIZE sizeof(AA_QUERY_CMD_LABEL) > + > +extern int aa_query_label(uint32_t mask, char *query, size_t size, int > *allow, > + int *audit); > + > #define __macroarg_counter(Y...) __macroarg_count1 ( , ##Y) > #define __macroarg_count1(Y...) __macroarg_count2 (Y, > 16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0) > #define > __macroarg_count2(_,x0,x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,n,Y...) > n > diff --git a/libraries/libapparmor/src/kernel_interface.c > b/libraries/libapparmor/src/kernel_interface.c > index ea1659d..356307e 100644 > --- a/libraries/libapparmor/src/kernel_interface.c > +++ b/libraries/libapparmor/src/kernel_interface.c > @@ -28,6 +28,9 @@ > #include <limits.h> > #include <stdarg.h> > #include <mntent.h> > +#include <inttypes.h> > +#include <stdint.h> inttypes.h already includes stdint.h. > +#include <pthread.h> > > #include "apparmor.h" > > @@ -650,3 +653,98 @@ int aa_getpeercon(int fd, char **con, char **mode) > > return size; > } > + > +static pthread_once_t aafs_access_control = PTHREAD_ONCE_INIT; > +static char *aafs_access = NULL; > + > +static void aafs_access_init_once(void) > +{ > + char *aafs; > + int ret; > + > + ret = aa_find_mountpoint(&aafs); > + if (ret < 0) > + return; > + > + ret = asprintf(&aafs_access, "%s/.access", aafs); > + if (ret < 0) > + aafs_access = NULL; > + > + free(aafs); > +} > + > +/* "allow 0x00000000\ndeny 0x00000000\naudit 0x00000000\nquiet 0x00000000\n" > */ > +#define QUERY_LABEL_REPLY_LEN 67 > + > +/** > + * aa_query_label - query the access(es) of a label > + * @mask: permission bits to query > + * @query: binary query string, must be offset by AA_QUERY_CMD_LABEL_SIZE > + * @size: size of the query string must include AA_QUERY_CMD_LABEL_SIZE > + * @allowed: upon successful return, will be 1 if query is allowed and 0 if > not > + * @audited: upon successful return, will be 1 if query should be audited > and 0 > + * if not > + * > + * Returns: 0 on success else -1 and sets errno > + */ > +int aa_query_label(uint32_t mask, char *query, size_t size, int *allowed, > + int *audited) > +{ > + char buf[QUERY_LABEL_REPLY_LEN]; > + uint32_t allow, deny, audit, quiet; > + int fd, ret, saved; > + > + if (!mask || size <= AA_QUERY_CMD_LABEL_SIZE) { > + errno = EINVAL; > + return -1; > + } > + > + ret = pthread_once(&aafs_access_control, aafs_access_init_once); > + if (ret) { > + errno = EINVAL; > + return -1; > + } else if (!aafs_access) { > + errno = ENOMEM; > + return -1; > + } > + > + fd = open(aafs_access, O_RDWR); > + if (fd == -1) > + return -1; > + > + memcpy(query, AA_QUERY_CMD_LABEL, AA_QUERY_CMD_LABEL_SIZE); > + errno = 0; > + ret = write(fd, query, size); > + if (ret != size) { > + if (ret >= 0) > + errno = EPROTO; > + return -1; > + } > + > + ret = read(fd, buf, QUERY_LABEL_REPLY_LEN); > + saved = errno; > + (void)close(fd); This may not be enough to silence the new-fangled warnings. > + errno = saved; > + if (ret != QUERY_LABEL_REPLY_LEN) { > + if (ret >= 0) > + errno = EPROTO; > + return -1; > + } > + > + ret = sscanf(buf, "allow 0x%8" SCNx32 "\n" > + "deny 0x%8" SCNx32 "\n" > + "audit 0x%8" SCNx32 "\n" > + "quiet 0x%8" SCNx32 "\n", > + &allow, &deny, &audit, &quiet); > + if (ret != 4) { > + errno = EPROTONOSUPPORT; > + return -1; > + } > + > + *allowed = mask & ~(allow & ~deny) ? 0 : 1; > + if (!(*allowed)) > + audit = 0xFFFFFFFF; > + *audited = mask & ~(audit & ~quiet) ? 0 : 1; I already broke my head thinking this bit through once -- and I came to the wrong conclusion last time :) -- so I hope this has the fix you found you needed last time through. :) > + > + return 0; > +} > diff --git a/libraries/libapparmor/src/libapparmor.map > b/libraries/libapparmor/src/libapparmor.map > index c4fcf8f..df696a7 100644 > --- a/libraries/libapparmor/src/libapparmor.map > +++ b/libraries/libapparmor/src/libapparmor.map > @@ -37,3 +37,10 @@ APPARMOR_1.1 { > local: > *; > } APPARMOR_1.0; > + > +APPARMOR_3.0 { > + global: > + aa_query_label; > + local: > + *; > +} APPARMOR_1.1; > diff --git a/libraries/libapparmor/swig/SWIG/libapparmor.i > b/libraries/libapparmor/swig/SWIG/libapparmor.i > index 1d3ca07..a94cb23 100644 > --- a/libraries/libapparmor/swig/SWIG/libapparmor.i > +++ b/libraries/libapparmor/swig/SWIG/libapparmor.i > @@ -27,3 +27,5 @@ extern int aa_gettaskcon(pid_t target, char **con, char > **mode); > extern int aa_getcon(char **con, char **mode); > extern int aa_getpeercon_raw(int fd, char *buf, int *len, char **mode); > extern int aa_getpeercon(int fd, char **con, char **mode); > +extern int aa_query_label(uint32_t mask, char *query, size_t size, int > *allow, > + int *audit); > -- Thanks!
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