1901
1901
command lines will not be invoked (this prevents possible infinite
1904
At first sight, it looks like the list of filenames to be processed
1905
can only be at the end of the command line, and that this might be a
1906
problem for some comamnds (@code{cp} and @code{rsync} for example).
1908
However, there is a slightly obscure but powerful workarouund for this
1909
problem which takes advantage of the behaviour of @code{sh -c}:-
1912
find startpoint -tests @dots{} -exec sh -c 'scp "$@@" remote:/dest' sh @{@} +
1915
In the example above, the filenames we want to work on need to occur
1916
on the @code{scp} command line before the name of the destination. We
1917
use the shell to invoke the command @code{scp "$@@" remote:/dest} and
1918
the shell expands @code{"$@@"} to the list of filenames we want to
1904
1921
Another, but less secure, way to run a command on more than one file
1905
1922
at once, is to use the @code{xargs} command, which is invoked like
2503
2520
programs and earlier releases of the GNU ones. @code{updatedb}
2504
2521
produces this format if given the @samp{--old-format} option.
2523
All versions of GNU @code{locate} prior to 4.2.31 fail to correctly
2524
handle very long file names, possibly leading to security problems
2525
relating to a heap buffer overrun. @xref{Security Considerations for
2526
locate}, for a detailed explanation.
2506
2528
@code{updatedb} runs programs called @code{bigram} and @code{code} to
2507
2529
produce old-format databases. The old format differs from the new one
2508
2530
in the following ways. Instead of each entry starting with an
2941
2963
this option means that @code{locate} will not be able to properly
2942
2964
handle non-ASCII characters in file names (that is, file names
2943
2965
containing characters which have the eighth bit set, such as many of
2944
the characters from the ISO-8859-1 character set).
2966
the characters from the ISO-8859-1 character set). Versions of
2967
@code{locate} prior to 4.2.31 fail to correctly handle long filenames
2968
in old-format databases.
2946
2970
Print a summary of the command line usage and exit.
2947
2971
@item --version
4364
4388
@node Security Considerations for locate
4365
4389
@section Security Considerations for @code{locate}
4391
@subsection Race Conditions
4367
4392
It is fairly unusual for the output of @code{locate} to be fed into
4368
4393
another command. However, if this were to be done, this would raise
4369
the same set of security issues as the use of @samp{find @dots{} -print}.
4370
Although the problems relating to whitespace in file names can be
4371
resolved by using @code{locate}'s @samp{-0} option, this still leaves
4372
the race condition problems associated with @samp{find @dots{} -print0}.
4373
There is no way to avoid these problems in the case of @code{locate}.
4394
the same set of security issues as the use of @samp{find @dots{}
4395
-print}. Although the problems relating to whitespace in file names
4396
can be resolved by the @samp{-0} option of @code{locate}, this still
4397
leaves the race condition problems associated with @samp{find @dots{}
4398
-print0}. There is no way to avoid these problems in the case of
4401
@subsection Long File Name Bugs with Old-Format Databases
4402
All versions of @code{locate} prior to 4.2.31 have a bug in the way
4403
that old-format databases are read. They read file names into a
4404
fixed-length 1026 byte buffer, allocated on the heap. This buffer is
4405
not extended if file names are too long to fit into the buffer. No
4406
range checking on the length of the filename is performed. This could
4407
in theory lead to a privilege escalation attack. Findutils versions
4408
4.3.0 to 4.3.6 are also affected.
4410
On systems using the old database format and affected versions of
4411
@code{locate}, carefully-chosen long file names could in theory allow
4412
malicious users to run code of their choice as any user invoking
4415
If remote users can choose the names of files stored on your system,
4416
and these files are indexed by @code{updatedb}, this may be a remote
4417
security vulnerability. Findutils version 4.2.31 fixes this problem.
4418
The @code{updatedb}, @code{bigram} and @code{code} programs do no
4419
appear to be affected.
4421
If you are also using GNU coreutils, you can use the following command
4422
to determine the length of the longest file name on a given system:
4425
find / -print0 | tr -c '\0' 'x' | tr '\0' '\n' | wc -L
4428
Although this problem is significant, the old database format is not
4429
the default, and use of the old database format is not common. Most
4430
installations and most users will not be affected by this problem.
4375
4433
@node Security Summary
4376
4434
@section Summary
added
removed
doc/find.texi
