diff options
| author | Helge Deller <deller@gmx.de> | 2022-12-05 12:38:25 +0100 |
|---|---|---|
| committer | Laurent Vivier <laurent@vivier.eu> | 2023-03-10 20:41:30 +0100 |
| commit | 258bec39f3e58fcdb006028e5c5a1801136ef04a (patch) | |
| tree | 9e7c2243752bd484a30868dacb22c5cebb892f4c /linux-user/main.c | |
| parent | 817fd33836e73812df2f1907612b57750fcb9491 (diff) | |
linux-user: Fix access to /proc/self/exe
When accsssing /proc/self/exe from a userspace program, linux-user tries
to resolve the name via realpath(), which may fail if the process
changed the working directory in the meantime.
An example:
- a userspace program ist started with ./testprogram
- the program runs chdir("/tmp")
- then the program calls readlink("/proc/self/exe")
- linux-user tries to run realpath("./testprogram") which fails
because ./testprogram isn't in /tmp
- readlink() will return -ENOENT back to the program
Avoid this issue by resolving the full path name of the started process
at startup of linux-user and store it in real_exec_path[]. This then
simplifies the emulation of readlink() and readlinkat() as well, because
they can simply copy the path string to userspace.
I noticed this bug because the testsuite of the debian package "pandoc"
failed on linux-user while it succeeded on real hardware. The full log
is here:
https://buildd.debian.org/status/fetch.php?pkg=pandoc&arch=hppa&ver=2.17.1.1-1.1%2Bb1&stamp=1670153210&raw=0
Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20221205113825.20615-1-deller@gmx.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Diffstat (limited to 'linux-user/main.c')
| -rw-r--r-- | linux-user/main.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/linux-user/main.c b/linux-user/main.c index 4ff30ff980..798fdc0bce 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -65,6 +65,7 @@ #endif char *exec_path; +char real_exec_path[PATH_MAX]; int singlestep; static const char *argv0; @@ -739,6 +740,11 @@ int main(int argc, char **argv, char **envp) } } + /* Resolve executable file name to full path name */ + if (realpath(exec_path, real_exec_path)) { + exec_path = real_exec_path; + } + /* * get binfmt_misc flags */ |