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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-02-18 15:58:16 -0500 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-03-13 16:50:16 -0300 |
commit | 9b646f5dc933dfa019f2ed7f80b6198b43e31f62 (patch) | |
tree | f9f36d3010ff3ae93287aae0e945bfb8d23efba5 /sysdeps/ieee754 | |
parent | dded0d20f67ba1925ccbcb9cf28f0c75febe0dbe (diff) | |
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elf: Canonicalize $ORIGIN in an explicit ld.so invocation [BZ 25263]
When an executable is invoked directly, we calculate $ORIGIN by calling
readlink on /proc/self/exe, which the Linux kernel resolves to the
target of any symlinks. However, if an executable is run through ld.so,
we cannot use /proc/self/exe and instead use the path given as an
argument. This leads to a different calculation of $ORIGIN, which is
most notable in that it causes ldd to behave differently (e.g., by not
finding a library) from directly running the program.
To make the behavior consistent, take advantage of the fact that the
kernel also resolves /proc/self/fd/ symlinks to the target of any
symlinks in the same manner, so once we have opened the main executable
in order to load it, replace the user-provided path with the result of
calling readlink("/proc/self/fd/N").
(On non-Linux platforms this resolution does not happen and so no
behavior change is needed.)
The __fd_to_filename requires _fitoa_word and _itoa_word, which for
32-bits pulls a lot of definitions from _itoa.c (due _ITOA_NEEDED
being defined). To simplify the build move the required function
to a new file, _fitoa_word.c.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Co-authored-by: Geoffrey Thomas <geofft@ldpreload.com>
Reviewed-by: Geoffrey Thomas <geofft@ldpreload.com>
Tested-by: Geoffrey Thomas <geofft@ldpreload.com>
Diffstat (limited to 'sysdeps/ieee754')
0 files changed, 0 insertions, 0 deletions