Bug#308561: ssh: sftp rename fails on filesystems that don't support hard links
Package: ssh
Version: 1:3.8.1p1-8.sarge.4
Severity: normal
Tags: patch
Using sftp to access FAT32 partitions often fails. Specifically, if a
rename is requested, the operation will fail with "permission denied"
when in fact the user is allowed to rename the file. The failure is
due to sftp-server's use of link(2) to avoid races. FAT32 does not
support hard-links. sftp-server does not properly handle a failure
return from link(2) and fall back to rename(2).
The patch below is partially a backport from 3.9p1 (I think), but that
version actually checks for an incorrect error identifier. link(2)
returns EPERM in this case, not EOPNOTSUPP.
--- sftp-server.c 2004-02-23 17:19:15.000000000 -0500
+++ ../openssh-3.8.1p1-patched/sftp-server.c 2005-05-11
00:44:59.000000000 -0400
@@ -839,9 +839,29 @@
status = errno_to_portable(errno);
else if (S_ISREG(sb.st_mode)) {
/* Race-free rename of regular files */
- if (link(oldpath, newpath) == -1)
- status = errno_to_portable(errno);
- else if (unlink(oldpath) == -1) {
+ if (link(oldpath, newpath) == -1) {
+ if (errno == EPERM
+#ifdef LINK_OPNOTSUPP_ERRNO
+ || errno == LINK_OPNOTSUPP_ERRNO
+#endif
+ ) {
+ struct stat st;
+
+ /*
+ * fs doesn't support links, so fall back to
+ * stat+rename. This is racy.
+ */
+ if (stat(newpath, &st) == -1) {
+ if (rename(oldpath, newpath) == -1)
+ status =
+
errno_to_portable(errno);
+ else
+ status = SSH2_FX_OK;
+ }
+ } else {
+ status = errno_to_portable(errno);
+ }
+ } else if (unlink(oldpath) == -1) {
status = errno_to_portable(errno);
/* clean spare link */
unlink(newpath);
-- System Information:
Debian Release: 3.1
APT prefers testing
APT policy: (700, 'testing'), (600, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.6.11.7
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Versions of packages ssh depends on:
ii adduser 3.63 Add and remove users and groups
ii debconf 1.4.49 Debian configuration
management sy
ii dpkg 1.10.27 Package maintenance system
for Deb
ii libc6 2.3.2.ds1-21 GNU C Library: Shared
libraries an
ii libpam-modules 0.76-22 Pluggable Authentication
Modules f
ii libpam-runtime 0.76-22 Runtime support for the PAM
librar
ii libpam0g 0.76-22 Pluggable Authentication
Modules l
ii libssl0.9.7 0.9.7e-3 SSL shared libraries
ii libwrap0 7.6.dbs-8 Wietse Venema's TCP
wrappers libra
ii zlib1g 1:1.2.2-4 compression library - runtime
-- debconf information excluded
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