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This patch will print cap_permitted and cap_inheritable data in the PATH
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records of any file that has file capabilities set.  Files which do not
have fcaps set will not have different PATH records.

An example audit record if you run:
setcap "cap_net_admin+pie" /bin/bash
/bin/bash

type=SYSCALL msg=audit(1225741937.363:230): arch=c000003e syscall=59 success=yes exit=0 a0=2119230 a1=210da30 a2=20ee290 a3=8 items=2 ppid=2149 pid=2923 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=3 comm="ping" exe="/bin/ping" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=EXECVE msg=audit(1225741937.363:230): argc=2 a0="ping" a1="www.google.com"
type=CWD msg=audit(1225741937.363:230):  cwd="/root"
type=PATH msg=audit(1225741937.363:230): item=0 name="/bin/ping" inode=49256 dev=fd:00 mode=0104755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ping_exec_t:s0 cap_fp=0000000000002000 cap_fi=0000000000002000 cap_fe=1 cap_fver=2
type=PATH msg=audit(1225741937.363:230): item=1 name=(null) inode=507915 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Eric Paris authored and James Morris committed Nov 11, 2008
1 parent c0b0044 commit 851f7ff
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Showing 2 changed files with 82 additions and 5 deletions.
5 changes: 5 additions & 0 deletions include/linux/capability.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ typedef struct __user_cap_data_struct {
#define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX

#define VFS_CAP_REVISION_MASK 0xFF000000
#define VFS_CAP_REVISION_SHIFT 24
#define VFS_CAP_FLAGS_MASK ~VFS_CAP_REVISION_MASK
#define VFS_CAP_FLAGS_EFFECTIVE 0x000001

Expand Down Expand Up @@ -534,6 +535,10 @@ kernel_cap_t cap_set_effective(const kernel_cap_t pE_new);

extern int capable(int cap);

/* audit system wants to get cap info from files as well */
struct dentry;
extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);

#endif /* __KERNEL__ */

#endif /* !_LINUX_CAPABILITY_H */
82 changes: 77 additions & 5 deletions kernel/auditsc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,7 @@
#include <linux/highmem.h>
#include <linux/syscalls.h>
#include <linux/inotify.h>
#include <linux/capability.h>

#include "audit.h"

Expand All @@ -84,6 +85,15 @@ int audit_n_rules;
/* determines whether we collect data for signals sent */
int audit_signals;

struct audit_cap_data {
kernel_cap_t permitted;
kernel_cap_t inheritable;
union {
unsigned int fE; /* effective bit of a file capability */
kernel_cap_t effective; /* effective set of a process */
};
};

/* When fs/namei.c:getname() is called, we store the pointer in name and
* we don't let putname() free it (instead we free all of the saved
* pointers at syscall exit time).
Expand All @@ -100,6 +110,8 @@ struct audit_names {
gid_t gid;
dev_t rdev;
u32 osid;
struct audit_cap_data fcap;
unsigned int fcap_ver;
};

struct audit_aux_data {
Expand Down Expand Up @@ -1171,6 +1183,35 @@ static void audit_log_execve_info(struct audit_context *context,
kfree(buf);
}

static void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
{
int i;

audit_log_format(ab, " %s=", prefix);
CAP_FOR_EACH_U32(i) {
audit_log_format(ab, "%08x", cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]);
}
}

static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
{
kernel_cap_t *perm = &name->fcap.permitted;
kernel_cap_t *inh = &name->fcap.inheritable;
int log = 0;

if (!cap_isclear(*perm)) {
audit_log_cap(ab, "cap_fp", perm);
log = 1;
}
if (!cap_isclear(*inh)) {
audit_log_cap(ab, "cap_fi", inh);
log = 1;
}

if (log)
audit_log_format(ab, " cap_fe=%d cap_fver=%x", name->fcap.fE, name->fcap_ver);
}

static void audit_log_exit(struct audit_context *context, struct task_struct *tsk)
{
int i, call_panic = 0;
Expand Down Expand Up @@ -1421,6 +1462,8 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
}
}

audit_log_fcaps(ab, n);

audit_log_end(ab);
}

Expand Down Expand Up @@ -1787,8 +1830,36 @@ static int audit_inc_name_count(struct audit_context *context,
return 0;
}


static inline int audit_copy_fcaps(struct audit_names *name, const struct dentry *dentry)
{
struct cpu_vfs_cap_data caps;
int rc;

memset(&name->fcap.permitted, 0, sizeof(kernel_cap_t));
memset(&name->fcap.inheritable, 0, sizeof(kernel_cap_t));
name->fcap.fE = 0;
name->fcap_ver = 0;

if (!dentry)
return 0;

rc = get_vfs_caps_from_disk(dentry, &caps);
if (rc)
return rc;

name->fcap.permitted = caps.permitted;
name->fcap.inheritable = caps.inheritable;
name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;

return 0;
}


/* Copy inode data into an audit_names. */
static void audit_copy_inode(struct audit_names *name, const struct inode *inode)
static void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
const struct inode *inode)
{
name->ino = inode->i_ino;
name->dev = inode->i_sb->s_dev;
Expand All @@ -1797,6 +1868,7 @@ static void audit_copy_inode(struct audit_names *name, const struct inode *inode
name->gid = inode->i_gid;
name->rdev = inode->i_rdev;
security_inode_getsecid(inode, &name->osid);
audit_copy_fcaps(name, dentry);
}

/**
Expand Down Expand Up @@ -1831,7 +1903,7 @@ void __audit_inode(const char *name, const struct dentry *dentry)
context->names[idx].name = NULL;
}
handle_path(dentry);
audit_copy_inode(&context->names[idx], inode);
audit_copy_inode(&context->names[idx], dentry, inode);
}

/**
Expand Down Expand Up @@ -1892,7 +1964,7 @@ void __audit_inode_child(const char *dname, const struct dentry *dentry,
if (!strcmp(dname, n->name) ||
!audit_compare_dname_path(dname, n->name, &dirlen)) {
if (inode)
audit_copy_inode(n, inode);
audit_copy_inode(n, NULL, inode);
else
n->ino = (unsigned long)-1;
found_child = n->name;
Expand All @@ -1906,7 +1978,7 @@ void __audit_inode_child(const char *dname, const struct dentry *dentry,
return;
idx = context->name_count - 1;
context->names[idx].name = NULL;
audit_copy_inode(&context->names[idx], parent);
audit_copy_inode(&context->names[idx], NULL, parent);
}

if (!found_child) {
Expand All @@ -1927,7 +1999,7 @@ void __audit_inode_child(const char *dname, const struct dentry *dentry,
}

if (inode)
audit_copy_inode(&context->names[idx], inode);
audit_copy_inode(&context->names[idx], NULL, inode);
else
context->names[idx].ino = (unsigned long)-1;
}
Expand Down

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