Fix coverity defects: CID 147531 147532 147533 147535

coverity scan CID:147531,type: Argument cannot be negative
- may copy data with negative size
coverity scan CID:147532,type: resource leaks
- may close a fd which is negative
coverity scan CID:147533,type: resource leaks
- may call pwrite64 with a negative size
coverity scan CID:147535,type: resource leaks
- may call fdopen with a negative fd

Reviewed-by: Richard Laager <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: GeLiXin <[email protected]>
Closes #5176 

2 files changed, 11 insertions, 6 deletions

diff --git a/lib/libshare/nfs.c b/lib/libshare/nfs.c
index d1b207e65..abcc1025b 100644..100755
--- a/lib/libshare/nfs.c
+++ b/lib/libshare/nfs.c
@@ -519,6 +519,7 @@ nfs_validate_shareopts(const char *shareopts)
 static boolean_t
 nfs_is_share_active(sa_share_impl_t impl_share)
 {
+	int fd;
 	char line[512];
 	char *tab, *cur;
 	FILE *nfs_exportfs_temp_fp;
@@ -526,7 +527,10 @@ nfs_is_share_active(sa_share_impl_t impl_share)
 	if (!nfs_available())
 		return (B_FALSE);
 
-	nfs_exportfs_temp_fp = fdopen(dup(nfs_exportfs_temp_fd), "r");
+	if ((fd = dup(nfs_exportfs_temp_fd)) == -1)
+		return (B_FALSE);
+
+	nfs_exportfs_temp_fp = fdopen(fd, "r");
 
 	if (nfs_exportfs_temp_fp == NULL ||
 	    fseek(nfs_exportfs_temp_fp, 0, SEEK_SET) < 0) {
diff --git a/lib/libzpool/kernel.c b/lib/libzpool/kernel.c
index 7ac505a64..60dda39a8 100644..100755
--- a/lib/libzpool/kernel.c
+++ b/lib/libzpool/kernel.c
@@ -668,7 +668,11 @@ vn_open(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2, int x3)
 	 * FREAD and FWRITE to the corresponding O_RDONLY, O_WRONLY, and O_RDWR.
 	 */
 	fd = open64(realpath, flags - FREAD, mode);
-	err = errno;
+	if (fd == -1) {
+		err = errno;
+		free(realpath);
+		return (err);
+	}
 
 	if (flags & FCREAT)
 		(void) umask(old_umask);
@@ -691,9 +695,6 @@ vn_open(char *path, int x1, int flags, int mode, vnode_t **vpp, int x2, int x3)
 
 	free(realpath);
 
-	if (fd == -1)
-		return (err);
-
 	if (fstat64_blk(fd, &st) == -1) {
 		err = errno;
 		close(fd);
@@ -740,7 +741,7 @@ vn_rdwr(int uio, vnode_t *vp, void *addr, ssize_t len, offset_t offset,
 
 	if (uio == UIO_READ) {
 		rc = pread64(vp->v_fd, addr, len, offset);
-		if (vp->v_dump_fd != -1) {
+		if (vp->v_dump_fd != -1 && rc != -1) {
 			int status;
 			status = pwrite64(vp->v_dump_fd, addr, rc, offset);
 			ASSERT(status != -1);