Imported Upstream version 2.22upstream/2.22

1 files changed, 321 insertions, 0 deletions

diff --git a/libcap/cap_file.c b/libcap/cap_file.c
new file mode 100644
index 0000000..634e601
--- /dev/null
+++ b/libcap/cap_file.c
@@ -0,0 +1,321 @@
+/*
+ * Copyright (c) 1997,2007 Andrew G Morgan <morgan@kernel.org>
+ *
+ * This file deals with setting capabilities on files.
+ */
+
+#include <sys/types.h>
+#include <sys/xattr.h>
+#include <byteswap.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define XATTR_SECURITY_PREFIX "security."
+
+#include "libcap.h"
+
+#ifdef VFS_CAP_U32
+
+#if VFS_CAP_U32 != __CAP_BLKS
+# error VFS representation of capabilities is not the same size as kernel
+#endif
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define FIXUP_32BITS(x) bswap_32(x)
+#else
+#define FIXUP_32BITS(x) (x)
+#endif
+
+static cap_t _fcaps_load(struct vfs_cap_data *rawvfscap, cap_t result,
+			 int bytes)
+{
+    __u32 magic_etc;
+    unsigned tocopy, i;
+
+    magic_etc = FIXUP_32BITS(rawvfscap->magic_etc);
+    switch (magic_etc & VFS_CAP_REVISION_MASK) {
+#ifdef VFS_CAP_REVISION_1
+    case VFS_CAP_REVISION_1:
+	tocopy = VFS_CAP_U32_1;
+	bytes -= XATTR_CAPS_SZ_1;
+	break;
+#endif
+
+#ifdef VFS_CAP_REVISION_2
+    case VFS_CAP_REVISION_2:
+	tocopy = VFS_CAP_U32_2;
+	bytes -= XATTR_CAPS_SZ_2;
+	break;
+#endif
+
+    default:
+	cap_free(result);
+	result = NULL;
+	return result;
+    }
+
+    /*
+     * Verify that we loaded exactly the right number of bytes
+     */
+    if (bytes != 0) {
+	cap_free(result);
+	result = NULL;
+	return result;
+    }
+
+    for (i=0; i < tocopy; i++) {
+	result->u[i].flat[CAP_INHERITABLE]
+	    = FIXUP_32BITS(rawvfscap->data[i].inheritable);
+	result->u[i].flat[CAP_PERMITTED]
+	    = FIXUP_32BITS(rawvfscap->data[i].permitted);
+	if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
+	    result->u[i].flat[CAP_EFFECTIVE]
+		= result->u[i].flat[CAP_INHERITABLE]
+		| result->u[i].flat[CAP_PERMITTED];
+	}
+    }
+    while (i < __CAP_BLKS) {
+	result->u[i].flat[CAP_INHERITABLE]
+	    = result->u[i].flat[CAP_PERMITTED]
+	    = result->u[i].flat[CAP_EFFECTIVE] = 0;
+	i++;
+    }
+
+    return result;
+}
+
+static int _fcaps_save(struct vfs_cap_data *rawvfscap, cap_t cap_d,
+		       int *bytes_p)
+{
+    __u32 eff_not_zero, magic;
+    unsigned tocopy, i;
+
+    if (!good_cap_t(cap_d)) {
+	errno = EINVAL;
+	return -1;
+    }
+
+    switch (cap_d->head.version) {
+#ifdef _LINUX_CAPABILITY_VERSION_1
+    case _LINUX_CAPABILITY_VERSION_1:
+	magic = VFS_CAP_REVISION_1;
+	tocopy = VFS_CAP_U32_1;
+	*bytes_p = XATTR_CAPS_SZ_1;
+	break;
+#endif
+
+#ifdef _LINUX_CAPABILITY_VERSION_2
+    case _LINUX_CAPABILITY_VERSION_2:
+	magic = VFS_CAP_REVISION_2;
+	tocopy = VFS_CAP_U32_2;
+	*bytes_p = XATTR_CAPS_SZ_2;
+	break;
+#endif
+
+#ifdef _LINUX_CAPABILITY_VERSION_3
+    case _LINUX_CAPABILITY_VERSION_3:
+	magic = VFS_CAP_REVISION_2;
+	tocopy = VFS_CAP_U32_2;
+	*bytes_p = XATTR_CAPS_SZ_2;
+	break;
+#endif
+
+    default:
+	errno = EINVAL;
+	return -1;
+    }
+
+    _cap_debug("setting named file capabilities");
+
+    for (eff_not_zero = 0, i = 0; i < tocopy; i++) {
+	eff_not_zero |= cap_d->u[i].flat[CAP_EFFECTIVE];
+    }
+    while (i < __CAP_BLKS) {
+	if ((cap_d->u[i].flat[CAP_EFFECTIVE]
+	     || cap_d->u[i].flat[CAP_INHERITABLE]
+	     || cap_d->u[i].flat[CAP_PERMITTED])) {
+	    /*
+	     * System does not support these capabilities
+	     */
+	    errno = EINVAL;
+	    return -1;
+	}
+	i++;
+    }
+
+    for (i=0; i < tocopy; i++) {
+	rawvfscap->data[i].permitted
+	    = FIXUP_32BITS(cap_d->u[i].flat[CAP_PERMITTED]);
+	rawvfscap->data[i].inheritable
+	    = FIXUP_32BITS(cap_d->u[i].flat[CAP_INHERITABLE]);
+
+	if (eff_not_zero
+	    && ((~(cap_d->u[i].flat[CAP_EFFECTIVE]))
+		& (cap_d->u[i].flat[CAP_PERMITTED]
+		   | cap_d->u[i].flat[CAP_INHERITABLE]))) {
+	    errno = EINVAL;
+	    return -1;
+	}
+    }
+
+    if (eff_not_zero == 0) {
+	rawvfscap->magic_etc = FIXUP_32BITS(magic);
+    } else {
+	rawvfscap->magic_etc = FIXUP_32BITS(magic|VFS_CAP_FLAGS_EFFECTIVE);
+    }
+
+    return 0;      /* success */
+}
+
+/*
+ * Get the capabilities of an open file, as specified by its file
+ * descriptor.
+ */
+
+cap_t cap_get_fd(int fildes)
+{
+    cap_t result;
+
+    /* allocate a new capability set */
+    result = cap_init();
+    if (result) {
+	struct vfs_cap_data rawvfscap;
+	int sizeofcaps;
+
+	_cap_debug("getting fildes capabilities");
+
+	/* fill the capability sets via a system call */
+	sizeofcaps = fgetxattr(fildes, XATTR_NAME_CAPS,
+			       &rawvfscap, sizeof(rawvfscap));
+	if (sizeofcaps < sizeof(rawvfscap.magic_etc)) {
+	    cap_free(result);
+	    result = NULL;
+	} else {
+	    result = _fcaps_load(&rawvfscap, result, sizeofcaps);
+	}
+    }
+
+    return result;
+}
+
+/*
+ * Get the capabilities from a named file.
+ */
+
+cap_t cap_get_file(const char *filename)
+{
+    cap_t result;
+
+    /* allocate a new capability set */
+    result = cap_init();
+    if (result) {
+	struct vfs_cap_data rawvfscap;
+	int sizeofcaps;
+
+	_cap_debug("getting filename capabilities");
+
+	/* fill the capability sets via a system call */
+	sizeofcaps = getxattr(filename, XATTR_NAME_CAPS,
+			      &rawvfscap, sizeof(rawvfscap));
+	if (sizeofcaps < sizeof(rawvfscap.magic_etc)) {
+	    cap_free(result);
+	    result = NULL;
+	} else {
+	    result = _fcaps_load(&rawvfscap, result, sizeofcaps);
+	}
+    }
+
+    return result;
+}
+
+/*
+ * Set the capabilities of an open file, as specified by its file
+ * descriptor.
+ */
+
+int cap_set_fd(int fildes, cap_t cap_d)
+{
+    struct vfs_cap_data rawvfscap;
+    int sizeofcaps;
+    struct stat buf;
+
+    if (fstat(fildes, &buf) != 0) {
+	_cap_debug("unable to stat file descriptor %d", fildes);
+	return -1;
+    }
+    if (S_ISLNK(buf.st_mode) || !S_ISREG(buf.st_mode)) {
+	_cap_debug("file descriptor %d for non-regular file", fildes);
+	errno = EINVAL;
+	return -1;
+    }
+
+    if (cap_d == NULL) {
+	_cap_debug("deleting fildes capabilities");
+	return fremovexattr(fildes, XATTR_NAME_CAPS);
+    } else if (_fcaps_save(&rawvfscap, cap_d, &sizeofcaps) != 0) {
+	return -1;
+    }
+
+    _cap_debug("setting fildes capabilities");
+
+    return fsetxattr(fildes, XATTR_NAME_CAPS, &rawvfscap, sizeofcaps, 0);
+}
+
+/*
+ * Set the capabilities of a named file.
+ */
+
+int cap_set_file(const char *filename, cap_t cap_d)
+{
+    struct vfs_cap_data rawvfscap;
+    int sizeofcaps;
+    struct stat buf;
+
+    if (lstat(filename, &buf) != 0) {
+	_cap_debug("unable to stat file [%s]", filename);
+	return -1;
+    }
+    if (S_ISLNK(buf.st_mode) || !S_ISREG(buf.st_mode)) {
+	_cap_debug("file [%s] is not a regular file", filename);
+	errno = EINVAL;
+	return -1;
+    }
+
+    if (cap_d == NULL) {
+	_cap_debug("removing filename capabilities");
+	return removexattr(filename, XATTR_NAME_CAPS);
+    } else if (_fcaps_save(&rawvfscap, cap_d, &sizeofcaps) != 0) {
+	return -1;
+    }
+
+    _cap_debug("setting filename capabilities");
+    return setxattr(filename, XATTR_NAME_CAPS, &rawvfscap, sizeofcaps, 0);
+}
+
+#else /* ie. ndef VFS_CAP_U32 */
+
+cap_t cap_get_fd(int fildes)
+{
+    errno = EINVAL;
+    return NULL;
+}
+
+cap_t cap_get_file(const char *filename)
+{
+    errno = EINVAL;
+    return NULL;
+}
+
+int cap_set_fd(int fildes, cap_t cap_d)
+{
+    errno = EINVAL;
+    return -1;
+}
+
+int cap_set_file(const char *filename, cap_t cap_d)
+{
+    errno = EINVAL;
+    return -1;
+}
+
+#endif /* def VFS_CAP_U32 */