Repost: Possible problem with mv in fileutils 4.1

[Dave Gotwisner]

I reported this to the list on July 8th, but, having seen no followup,
and still having the problem, I am reasking/re-reporting.



There may be a problem with the 4.1 version of mv, when moving a file
onto another read-only file.  In fileutils 4.0p (redhat 6.2) this
failed, as expected.  In fileutils 4.1 (redhat 7.3) it succeeded, as it
shouldn't have (my opinion).  Filesystem is an ext2 (for fu4.0p) and
ext3 (for fu4.1), but I doubt that makes a difference.  Here is a simple

test procedure:

#!/bin/sh
uname -a
touch foo1 foo2
chmod 400 foo1 foo2

# This will generate an error, as expected:
rm foo1

# This will generate an error, as expected:
cp foo1 foo2

# The following command will perform incorrectly (imho), actually
# removing foo2, and replacing it with the contents of foo1.  Foo1
# (the name, not the inode) will no longer exist.
mv foo1 foo2


As noted, the "rm" will generate "rm: remove write-protected file
`foo1'?" which is as expected.  The "cp" generates a "cp: cannot create
regular file `foo2': Permission denied" message, which is also as
expected.

With fu4.0p, the "mv" generates "mv: overwrite `foo2', overriding mode
0400?' which is correct.  fu4.1 generates no error and renames the
file.

If I do strace's of the two mv commands, the old one checked for
permissions prior to moving, the new does not (which I feel is wrong).

Is this a bug, or am I mistaken?

Note that in looking at the code, it looks like it
calls some internal glibc functions, which may be (and probably are) at
fault, but I thought
that I would check here first.

Thanks,

    Dave


##################################
##################################
##################################
##################################
Fileutils 4.0p strace:

execve("/bin/mv", ["mv", "foo1", "foo2"], [/* 26 vars */]) = 0
brk(0)                                  = 0x80531f0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40014000
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=34685, ...}) = 0
old_mmap(NULL, 34685, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40015000
close(3)                                = 0
open("/lib/libc.so.6", O_RDONLY)        = 3
fstat(3, {st_mode=S_IFREG|0755, st_size=4101324, ...}) = 0
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\210\212"...,
4096) = 4096
old_mmap(NULL, 1001564, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) =
0x4001e000
mprotect(0x4010b000, 30812, PROT_NONE)  = 0
old_mmap(0x4010b000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED,

3, 0xec000) = 0x4010b000
old_mmap(0x4010f000, 14428, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4010f000
close(3)                                = 0
mprotect(0x4001e000, 970752, PROT_READ|PROT_WRITE) = 0
mprotect(0x4001e000, 970752, PROT_READ|PROT_EXEC) = 0
munmap(0x40015000, 34685)               = 0
personality(PER_LINUX)                  = 0
getpid()                                = 17107
brk(0)                                  = 0x80531f0
brk(0x8053228)                          = 0x8053228
brk(0x8054000)                          = 0x8054000
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
fstat64(0x3, 0xbfffb6ac)                = -1 ENOSYS (Function not
implemented)
fstat(3, {st_mode=S_IFREG|0644, st_size=2265, ...}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40015000
read(3, "# Locale name alias data base.\n#"..., 4096) = 2265
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0x40015000, 4096)                = 0
open("/usr/share/i18n/locale.alias", O_RDONLY) = -1 ENOENT (No such file

or directory)
open("/usr/share/locale/en_US/LC_MESSAGES", O_RDONLY) = 3
fstat(3, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
close(3)                                = 0
open("/usr/share/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES", O_RDONLY) =
3
fstat(3, {st_mode=S_IFREG|0644, st_size=44, ...}) = 0
old_mmap(NULL, 44, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40015000
close(3)                                = 0
open("/usr/share/locale/en_US/LC_MONETARY", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=93, ...}) = 0
old_mmap(NULL, 93, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40016000
close(3)                                = 0
open("/usr/share/locale/en_US/LC_COLLATE", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=29970, ...}) = 0
old_mmap(NULL, 29970, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40113000
close(3)                                = 0
brk(0x8055000)                          = 0x8055000
open("/usr/share/locale/en_US/LC_TIME", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=508, ...}) = 0
old_mmap(NULL, 508, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40017000
close(3)                                = 0
open("/usr/share/locale/en_US/LC_NUMERIC", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=27, ...}) = 0
old_mmap(NULL, 27, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40018000
close(3)                                = 0
open("/usr/share/locale/en_US/LC_CTYPE", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=87756, ...}) = 0
old_mmap(NULL, 87756, PROT_READ, MAP_PRIVATE, 3, 0) = 0x4011b000
close(3)                                = 0
geteuid()                               = 500
umask(0)                                = 02
stat("foo2", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
lstat("foo1", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
lstat("foo2", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
access("foo2", W_OK)                    = -1 EACCES (Permission denied)
open("/usr/share/locale/en_US/LC_MESSAGES/fileutils.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/fileutils.mo", O_RDONLY) = -1
ENOENT (No such file or directory)

write(2, "mv: overwrite `foo2\', overriding"..., 44mv: overwrite `foo2',

overriding mode 0400? ) = 44
fstat(0, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 2), ...}) = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40019000
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
read(0,
"\n", 1024)                     = 1
brk(0x8056000)                          = 0x8056000
_exit(1)                                = ?


##################################
##################################
##################################
##################################
The strace for the 4.1 fileutils is the following:


execve("/bin/mv", ["mv", "foo1", "foo2"], [/* 30 vars */]) = 0
uname({sys="Linux", node="dellunix.gotwisner.net", ...}) = 0
brk(0)                                  = 0x8053a04
open("/etc/ld.so.preload", O_RDONLY)    = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=118112, ...}) = 0
old_mmap(NULL, 118112, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40014000
close(3)                                = 0
open("/lib/i686/libc.so.6", O_RDONLY)   = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`u\1B4\0"...,
1024) = 1024
fstat64(3, {st_mode=S_IFREG|0755, st_size=1401027, ...}) = 0
old_mmap(0x42000000, 1264928, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) =
0x42000000
mprotect(0x4212c000, 36128, PROT_NONE)  = 0
old_mmap(0x4212c000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED,

3, 0x12c000) = 0x4212c000
old_mmap(0x42131000, 15648, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x42131000
close(3)                                = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x40031000
munmap(0x40014000, 118112)              = 0
brk(0)                                  = 0x8053a04
brk(0x8053a34)                          = 0x8053a34
brk(0x8054000)                          = 0x8054000
geteuid32()                             = 500
umask(0)                                = 02
stat64("foo2", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
brk(0x8055000)                          = 0x8055000
lstat64("foo1", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
lstat64("foo2", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
rename("foo1", "foo2")                  = 0
_exit(0)                                = ?