scanelf - Man Page

scanelf [options] ELFs or directories

scanelf is a user-space utility to quickly scan given ELFs, directories, or common system paths for different information. This may include ELF types, their PaX markings, TEXTRELs, etc...

-A,  --archives

Scan archives (.a files)

-a,  --all

Print all useful/simple info

-B,  --nobanner

Don't display the header

-b,  --bind

Print symbol binding information (lazy or now)

-D,  --endian

Print ELF endianness (big/little/...)

-E,  --etype ETYPE

Print only ELF files matching specified etype (like ET_DYN, ET_EXEC, etc...)

-e,  --header

Print GNU_STACK markings

-F,  --format FORMAT

Use specified format for output; see the Format section for more information

-f,  --from FILE

Read input stream from specified filename

-g,  --gmatch

Use strncmp to match libraries (use with -N). Or regexp with symbol matching

-h,  --help

Show condensed usage and exit

-I,  --osabi

Print OSABI

-i,  --interp

Print the interpreter information (.interp/PT_INTERP)

-k,  --section SECTION

Find ELFs with the specified section. May be specified multiple times to match multiple sections simultaneously. See Section Matching for more info.

-L,  --ldcache

Utilize ld.so.cache information (use with -r/-n)

-l,  --ldpath

Scan all directories in /etc/ld.so.conf

-M,  --bits BITS

Print only ELF files matching specified numeric bits (like 32/64)

-m,  --mount

Don't recursively cross mount points

-N,  --lib SONAME

Find ELFs that need the specified SONAME. May be specified multiple times to match multiple SONAMEs simultaneously. See SONAME MATCHING for more info.

-n,  --needed

Print libraries the ELF is linked against (DT_NEEDED)

-O,  --perms PERMS

Print only ELF files with matching specified octal bits (like 755)

-o,  --file FILE

Write output stream to specified filename

-p,  --path

Scan all directories in PATH environment

-q,  --quiet

Only output 'bad' things

-R,  --recursive

Scan directories recursively

-r,  --rpath

Print runpaths encoded in the ELF (DT_RPATH/DT_RUNPATH)

-S,  --soname

Print the ELF's shared library name (DT_SONAME)

-s,  --symbol SYMBOL

Find the specified symbol; see Symbol Matching for more info

-T,  --textrels

Locate cause of TEXTRELs via objdump

-t,  --textrel

Print TEXTREL information

-V,  --version

Print version and exit

-v,  --verbose

Be verbose (can be used more than once)

-X,  --fix

Try and 'fix' bad things (use with -r/-e)

-x,  --pax

Print PaX markings

-Y,  --eabi

Print EABI (only matters for a few architectures)

-y,  --symlink

Don't scan symlinks

-Z,  --size SIZE

Print ELF file size

-z,  --setpax FLAGS

Sets EI_PAX/PT_PAX_FLAGS to specified flags (use with -Xx)

--use-ldpath

Use the ld.so.conf paths to find the full path to libraries (use in conjunction with --needed).

--root PATH

Search the specified root tree instead of /. Generally paired with options like -l or -p. This implicitly treats all paths specified on the command line as relative to the root, so be sure to omit it if you are explicitly listing ELFs.

--ldcache PATH

Use specified path instead of /etc/ld.so.cache. Generally paired with options like -L or -n.

The format string is much like a printf string in that it is a literal string with flags requesting different information. For example, you could use a format string and expect the following results.

  # scanelf -BF "file %f needs %n; funky time" /bin/bash
  file bash needs libncurses.so.5,libdl.so.2,libc.so.6; funky time

Note that when you use a format string, generally information related flags should be omitted. In other words, you do not want to try and request NEEDED output (-n) and try to specify a format output at the same time as these operations are mutually exclusive. Each information related flag has an equivalent conversion specifier, so use those instead. You can of course continue to use non-information related flags (such as --verbose).

There are three characters that introduce conversion specifiers.

· % - replace with info

• # - silent boolean match
• + - verbose match

And there are a number of conversion specifiers. We try to match up the specifier with corresponding option.

· a - machine (EM) type

• b - bind flags
• e - program headers
• D - endian
• I - osabi
• Y - eabi
• F - long filename
• f - short filename
• i - interp
• k - section
• M - EI class
• N - specified needed
• n - needed libraries
• p - filename (minus search)
• o - etype
• O - perms
• r - runpaths
• S - SONAME
• s - symbol
• T - all textrels
• t - textrel status
• x - pax flags

The string specified takes the form [%[modifiers]%][[+-]<symbol name>][,[.....]].

If the symbol name is empty, then all symbols are matched.

If the symbol name is a glob ("*"), then all symbols are dumped in a debug format. Do not rely on the structure of this output as it changes whenever we feel like it.

If the first char of the symbol name is a plus ("+"), then only match defined symbols. If it's a minus ("-"), only match undefined symbols. When we say "defined", we mean the symbol is defined in the ELF vs having an external reference.

Putting modifiers in between the percent signs ("%") allows for more in depth filters. There are groups of modifiers. If you don't specify a member of a group, then all types in that group are matched.

· STT group (symbol type)

• n - STT_NOTYPE
• o - STT_OBJECT
• f - STT_FUNC
• F - STT_FILE
• STB group (symbol binding)
• l - STB_LOCAL
• g - STB_GLOBAL
• w - STB_WEAK
• STV group (symbol visibility)
• p - STV_DEFAULT
• i - STV_INTERNAL
• h - STV_HIDDEN
• P - STV_PROTECTED
• SHN group (section header)
• d - defined
• u - SHN_UNDEF
• a - SHN_ABS
• c - SHN_COMMON

You can search for multiple symbols simultaneously by using a comma (",") to separate different searches. Every symbol that matches will be displayed while unmatched symbols will not.

You can narrow your search by specifying the ELF object file type (ETYPE). The commandline option takes the numeric value and or symbolic type. Multiple values can be passed comma separated. Example -E ET_EXEC,ET_DYN,1

Here is the normal list available for your pleasure. You of course are free to specify any numeric value you want.

· 0 - ET_NONE - unknown type

• 1 - ET_REL - relocatable file
• 2 - ET_EXEC - executable file
• 3 - ET_DYN - shared object
• 4 - ET_CORE - core file

You can also narrow your search by specifying the ELF bitsize. Again, specify the numeric value or the symbolic define.

· 32 - ELFCLASS32 - 32bit ELFs

• 64 - ELFCLASS64 - 64bit ELFs

A ! prefix will only show ELF's that do not have the specified section.

A ! prefix will only show ELF's that do not depend on the specified library.

https://wiki.gentoo.org/wiki/Hardened/PaX_Utilities

Please include as much information as possible (using any available debugging options) and send bug reports to the maintainers (see the Authors section). Please use the Gentoo bugzilla at https://bugs.gentoo.org/ if possible.

chpax(1), dumpelf(1), paxctl(1), pspax(1), readelf(1), scanelf(1), elf(5)

Ned Ludd <solar@gentoo.org>

Mike Frysinger <vapier@gentoo.org>

Fabian Groffen <grobian@gentoo.org>

1. https://wiki.gentoo.org/wiki/Hardened/PaX_Utilities
2. https://bugs.gentoo.org/

dumpelf(1), pspax(1), scanmacho(1).