[PATCH v2 0/3] Incremental against [exports] rootdir patchset

[PATCH v2 0/3] Incremental against [exports] rootdir patchset

[Trond Myklebust]

These patches fix up a couple of bugs and issues against the [exports]
rootdir patchset for nfs-utils.

v2:
 - Fix nfsd_path_strip_root() return value, as pointed out by Bruce
 - Fix a strlen() bug in nfsd_path_strip_root()

Trond Myklebust (3):
  mountd: Fix up incorrect comparison in next_mnt()
  mountd: Ensure nfsd_path_strip_root() uses the canonicalised path
  mountd: Canonicalise the rootdir in exportent_mkrealpath()

 support/export/export.c  | 12 ++++++++++--
 support/misc/nfsd_path.c | 17 ++++++++++++-----
 utils/mountd/cache.c     |  8 +++++---
 3 files changed, 27 insertions(+), 10 deletions(-)

-- 
2.21.0

[PATCH v2 1/3] mountd: Fix up incorrect comparison in next_mnt()

[Trond Myklebust]

We want to ensure that we compare the full name of the last component.

Reported-by: "J. Bruce Fields" <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 utils/mountd/cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index d818c971bded..d616d526667e 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -400,7 +400,7 @@ static char *next_mnt(void **v, char *p)
 	while ((me = getmntent(f)) != NULL && l > 1) {
 		mnt_dir = nfsd_path_strip_root(me->mnt_dir);
 
-		if (strncmp(mnt_dir, p, l) == 0 && mnt_dir[l] != '/')
+		if (strncmp(mnt_dir, p, l) == 0 && mnt_dir[l] == '/')
 			return mnt_dir;
 	}
 	endmntent(f);
-- 
2.21.0

[PATCH v2 2/3] mountd: Ensure nfsd_path_strip_root() uses the canonicalised path

[Trond Myklebust]

When attempting to strip the root path, we should first canonicalise
the root pathname.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 support/misc/nfsd_path.c | 17 ++++++++++++-----
 utils/mountd/cache.c     |  6 ++++--
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/support/misc/nfsd_path.c b/support/misc/nfsd_path.c
index 2f41a793c534..84e48028071c 100644
--- a/support/misc/nfsd_path.c
+++ b/support/misc/nfsd_path.c
@@ -1,6 +1,7 @@
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -62,13 +63,19 @@ nfsd_path_nfsd_rootdir(void)
 char *
 nfsd_path_strip_root(char *pathname)
 {
+	char buffer[PATH_MAX];
 	const char *dir = nfsd_path_nfsd_rootdir();
-	char *ret;
 
-	ret = strstr(pathname, dir);
-	if (!ret || ret != pathname)
-		return pathname;
-	return pathname + strlen(dir);
+	if (!dir)
+		goto out;
+
+	if (realpath(dir, buffer))
+		return strstr(pathname, buffer) == pathname ?
+			pathname + strlen(buffer) : NULL;
+
+	xlog(D_GENERAL, "%s: failed to resolve path %s: %m", __func__, dir);
+out:
+	return pathname;
 }
 
 char *
diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index d616d526667e..ecda18c75a0f 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -390,7 +390,6 @@ static char *next_mnt(void **v, char *p)
 	FILE *f;
 	struct mntent *me;
 	size_t l = strlen(p);
-	char *mnt_dir = NULL;
 
 	if (*v == NULL) {
 		f = setmntent("/etc/mtab", "r");
@@ -398,7 +397,10 @@ static char *next_mnt(void **v, char *p)
 	} else
 		f = *v;
 	while ((me = getmntent(f)) != NULL && l > 1) {
-		mnt_dir = nfsd_path_strip_root(me->mnt_dir);
+		char *mnt_dir = nfsd_path_strip_root(me->mnt_dir);
+
+		if (!mnt_dir)
+			continue;
 
 		if (strncmp(mnt_dir, p, l) == 0 && mnt_dir[l] == '/')
 			return mnt_dir;
-- 
2.21.0

[PATCH v2 3/3] mountd: Canonicalise the rootdir in exportent_mkrealpath()

[Trond Myklebust]

Ensure that we canonicalise the export path when generating the
real path.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 support/export/export.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/support/export/export.c b/support/export/export.c
index 82bbb54c5e9e..c753f68e4d63 100644
--- a/support/export/export.c
+++ b/support/export/export.c
@@ -14,6 +14,7 @@
 #include <sys/types.h>
 #include <sys/param.h>
 #include <netinet/in.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <dirent.h>
 #include <errno.h>
@@ -21,6 +22,7 @@
 #include "nfslib.h"
 #include "exportfs.h"
 #include "nfsd_path.h"
+#include "xlog.h"
 
 exp_hash_table exportlist[MCL_MAXTYPES] = {{NULL, {{NULL,NULL}, }}, }; 
 static int export_hash(char *);
@@ -38,8 +40,14 @@ exportent_mkrealpath(struct exportent *eep)
 	const char *chroot = nfsd_path_nfsd_rootdir();
 	char *ret = NULL;
 
-	if (chroot)
-		ret = nfsd_path_prepend_dir(chroot, eep->e_path);
+	if (chroot) {
+		char buffer[PATH_MAX];
+		if (realpath(chroot, buffer))
+			ret = nfsd_path_prepend_dir(buffer, eep->e_path);
+		else
+			xlog(D_GENERAL, "%s: failed to resolve path %s: %m",
+					__func__, chroot);
+	}
 	if (!ret)
 		ret = xstrdup(eep->e_path);
 	eep->e_realpath = ret;
-- 
2.21.0