For origin xattr, use fid in ovl_fh to consume file_handle, and use
open_by_handle_at to check validity of the origin ovl_fh. In auto mode,
the invalid origin xattr will remove automatic.
Signed-off-by: yangerkun <yangerkun@xxxxxxxxxx>
---
check.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
lib.c | 10 +++++
lib.h | 4 +-
overlayfs.c | 23 +++++++++++
overlayfs.h | 33 +++++++++++++++
5 files changed, 202 insertions(+), 3 deletions(-)
diff --git a/check.c b/check.c
index e109620..50c4585 100644
--- a/check.c
+++ b/check.c
@@ -24,6 +24,7 @@
#include <stdlib.h>
#include <stdio.h>
+#include <stddef.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
@@ -169,11 +170,42 @@ static int ovl_get_redirect(int dirfd, const char *pathname,
return 0;
}
+/*
+ * Get the origin file handle with the pathname, then check the validity of member
+ * in ovl_fh.
+ */
+static int ovl_get_fh(int dirfd, const char *pathname,
+ struct ovl_fh **fh, bool *invalid)
+{
+ char *og = NULL;
+ ssize_t ret;
+
+ ret = get_xattr(dirfd, pathname, OVL_ORIGIN_XATTR, &og, NULL);
+ if (ret <= 0)
+ return ret;
+
+ ret = ovl_check_fh_len((struct ovl_fh *)og, ret);
+ if (ret) {
+ free(og);
+ if (ret == -EINVAL)
+ *invalid = true;
+ } else {
+ *fh = (struct ovl_fh *)og;
+ }
+
+ return 0;
+}
+
static inline int ovl_remove_redirect(int dirfd, const char *pathname)
{
return remove_xattr(dirfd, pathname, OVL_REDIRECT_XATTR);
}
+static inline int ovl_remove_origin(int dirfd, const char *pathname)
+{
+ return remove_xattr(dirfd, pathname, OVL_ORIGIN_XATTR);
+}
+
static inline int ovl_create_whiteout(int dirfd, const char *pathname)
{
if (mknodat(dirfd, pathname, S_IFCHR | WHITEOUT_MOD, makedev(0, 0))) {
@@ -758,6 +790,97 @@ out:
}
/*
+ * Get origin file handle stored in the xattr, check it's invalid
+ * or not. In auto-mode, invalid origin xattr will be removed directly.
+ */
+static int ovl_check_origin(struct scan_ctx *sctx)
+{
+ struct ovl_fh *fh = NULL;
+ struct file_handle *fhp = NULL;
+ struct stat stat;
+ bool invalid = false;
+ int i;
+ int ret;
+ int fid_len;
+ int fd;
+
+ /* Get origin */
+ ret = ovl_get_fh(sctx->dirfd, sctx->pathname, &fh, &invalid);
+ if (ret < 0)
+ return -1;
+
+ /* Cannot get ovl_fh, maybe not set or unrecognized */
+ if (!fh && !invalid)
+ return 0;
+
+ print_debug(_("File or dir \"%s\" has origin\n"), sctx->pathname);
+ sctx->t_origins++;
+
+ /* ovl_fh is invalid */
+ if (invalid)
+ goto remove;
+
+ /* Origin file in last lower dir? */
+ if (sctx->dirtype == OVL_LOWER && sctx->stack == lower_num -1)
+ goto remove;
+
+ fid_len = fh->len - offsetof(struct ovl_fh, fid);
+ fhp = smalloc(sizeof(struct file_handle) + fid_len);
+ fhp->handle_bytes = fh->len - offsetof(struct ovl_fh, fid);
+ fhp->handle_type = fh->type;
+ memcpy(fhp->f_handle, fh->fid, fid_len);
+
+ /* Scan lower directories to check origin xattr's validity */
+ i = sctx->dirtype == OVL_UPPER ? 0 : sctx->stack + 1;
+ for (; i < lower_num; i++) {
+ fd = open_by_handle_at(lowerfd[i], fhp, O_RDONLY);
+
+ if (fd == -1) {
+ if (errno == ESTALE || errno == ENOENT)
+ continue;
+
+ print_err(_("Error open_by_handle_at %s:%s\n"),
+ sctx->pathname, strerror(errno));
+ ret = -1;
+ goto out;
+ }
+
+ ret = fstat(fd, &stat);
+ if (ret) {
+ print_err(_("Cannot fstat origin file in %s of %s:%s\n"),
+ lowerdir[i], sctx->pathname, strerror(errno));
+ goto out2;
+ }
+
+ if (stat.st_mode != sctx->st->st_mode)
+ goto remove;
+
+ goto out2;
+ }
+
+remove:
+ sctx->i_origins++;
+
+ /* Remove origin xattr or ask user */
+ if (!ovl_ask_action("Invalid origin xattr", sctx->pathname, sctx->dirtype,
+ sctx->stack, "Remove origin", 1))
+ goto out;
+
+ ret = ovl_remove_origin(sctx->dirfd, sctx->pathname);
+ if (ret)
+ goto out;
+
+ sctx->i_origins--;
+ sctx->t_origins--;
+out2:
+ close(fd);
+out:
+ free(fhp);
+ free(fh);
+ return ret;
+}
+
+/*
* If a directory has origin target and redirect/merge subdirectories in it,
* it may contain copied up targets. In order to avoid 'd_ino' change after
* lower target copy-up or rename (which will create a new inode),
@@ -870,9 +993,11 @@ static struct scan_operations ovl_scan_ops[OVL_SCAN_PASS][2] = {
.whiteout = ovl_check_whiteout,
.impurity = ovl_count_impurity,
.impure = ovl_check_impure,
+ .origin = ovl_check_origin,
},
[OVL_LOWER] = {
.whiteout = ovl_check_whiteout,
+ .origin = ovl_check_origin,
},
}/* Pass Two */
};
@@ -892,11 +1017,12 @@ static void ovl_scan_report(struct scan_ctx *sctx)
{
if (flags & FL_VERBOSE) {
print_info(_("Scan %d directories, %d files, "
- "%d/%d whiteouts, %d/%d redirect dirs "
- "%d missing impure\n"),
+ "%d/%d whiteouts, %d/%d redirect dirs, "
+ "%d/%d origins, %d missing impure\n"),
sctx->directories, sctx->files,
sctx->i_whiteouts, sctx->t_whiteouts,
sctx->i_redirects, sctx->t_redirects,
+ sctx->i_origins, sctx->t_origins,
sctx->m_impure);
}
}
@@ -916,6 +1042,11 @@ static void ovl_scan_check(struct scan_ctx *sctx)
sctx->i_redirects);
incons = true;
}
+ if (sctx->i_origins) {
+ print_info(_("Invalid origins %d left!\n"),
+ sctx->i_origins);
+ incons = true;
+ }
if (sctx->m_impure) {
print_info(_("Directories %d missing impure xattr!\n"),
sctx->m_impure);
diff --git a/lib.c b/lib.c
index 4d9536a..2aee0dc 100644
--- a/lib.c
+++ b/lib.c
@@ -244,6 +244,11 @@ int scan_dir(struct scan_ctx *sctx, struct scan_operations *sop)
ret = scan_check_entry(sop->impurity, sctx);
if (ret)
goto out;
+
+ /* Check origins */
+ ret = scan_check_entry(sop->origin, sctx);
+ if (ret)
+ goto out;
break;
case FTS_DEFAULT:
/* Check whiteouts */
@@ -264,6 +269,11 @@ int scan_dir(struct scan_ctx *sctx, struct scan_operations *sop)
if (ret)
goto out;
+ /* Check origins */
+ ret = scan_check_entry(sop->origin, sctx);
+ if (ret)
+ goto out;
+
/* Save current dir data and create new one for subdir */
ftsent->fts_pointer = sctx->dirdata;
sctx->dirdata = smalloc(sizeof(struct scan_dir_data));
diff --git a/lib.h b/lib.h
index 880a8c3..5f7fdaa 100644
--- a/lib.h
+++ b/lib.h
@@ -71,7 +71,9 @@ struct scan_ctx {
int i_whiteouts; /* invalid whiteouts */
int t_redirects; /* total redirect dirs */
int i_redirects; /* invalid redirect dirs */
- int m_impure; /* missing inpure dirs */
+ int t_origins; /* total origins */
+ int i_origins; /* invalid origins */
+ int m_impure; /* missing impure dirs */
const char *pathname; /* path relative to overlay root */
const char *filename; /* filename */
diff --git a/overlayfs.c b/overlayfs.c
index 93b4cad..c2f0840 100644
--- a/overlayfs.c
+++ b/overlayfs.c
@@ -19,6 +19,8 @@
*/
#include <stddef.h>
+#include <errno.h>
+#include "overlayfs.h"
/*
* Split directories to individual one.
@@ -70,3 +72,24 @@ char *ovl_next_opt(char **s)
*s = NULL;
return sbegin;
}
+
+/*
+ * Check the validity of ovl_fh.
+ */
+int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
+{
+ if (fh_len < sizeof(struct ovl_fh) || fh_len < fh->len)
+ return -EINVAL;
+
+ if (fh->magic != OVL_FH_MAGIC)
+ return -EINVAL;
+
+ if (fh->version > OVL_FH_VERSION || fh->flags & ~OVL_FH_FLAG_ALL)
+ return -ENODATA;
+
+ if (!(fh->flags & OVL_FH_FLAG_ANY_ENDIAN) &&
+ (fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
+ return -ENODATA;
+
+ return 0;
+}
diff --git a/overlayfs.h b/overlayfs.h
index e3798aa..9913912 100644
--- a/overlayfs.h
+++ b/overlayfs.h
@@ -42,7 +42,40 @@
#define OVL_ORIGIN_XATTR "trusted.overlay.origin"
#define OVL_IMPURE_XATTR "trusted.overlay.impure"
+#define OVL_FH_VERSION 0
+#define OVL_FH_MAGIC 0xfb
+
+#define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
+#define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
+#define OVL_FH_FLAG_PATH_UPPER (1 << 2)
+#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
+ OVL_FH_FLAG_PATH_UPPER)
+#include <endian.h>
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define OVL_FH_FLAG_CPU_ENDIAN 0
+#elif __BYTE_ORDER == __BIG_ENDIAN
+#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
+#else
+#error Endianness not defined
+#endif
+
+#include <stdint.h>
+typedef struct {
+ uint8_t b[16];
+}uuid_t;
+
+struct ovl_fh {
+ uint8_t version;
+ uint8_t magic;
+ uint8_t len;
+ uint8_t flags;
+ uint8_t type;
+ uuid_t uuid;
+ uint8_t fid[0];
+};
+
unsigned int ovl_split_lowerdirs(char *lower);
char *ovl_next_opt(char **s);
+int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
#endif /* OVL_OVERLAYFS_H */
--
2.13.6
--
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