Upon further investigation, it looks like the Linux kernel opens the
core file with "O_CREAT | O_NOFOLLOW | O_LARGEFILE", then performs the
checks listed core(5):
http://lxr.linux.no/linux+v2.6.26.3/fs/exec.c#L1749
Apport appears to change its uid/gid to the failing process, then tries
to open the core file with "O_WRONLY | O_CREAT | O_EXCL". This takes
care of the permission check specified in core(5), but it doesn't handle
any of the others. In particular, using O_EXCL, means it doesn't
overwrite pre-existing core files, which is the source of my original
complaint.
core(5) says core files should be created except in the following cases:
* The process does not have permission to write the core file.
(By default the core file is called core, and is created in the
current working directory. See below for details on naming.)
Writing the core file will fail if the directory in which it is
to be created is non-writable, or if a file with the same name
exists and is not writable or is not a regular file (e.g., it is
a directory or a symbolic link).
* A (writable, regular) file with the same name as would be used
for the core dump already exists, but there is more than one
hard link to that file.
* The file system where the core dump file would be created is
full; or has run out of inodes; or is mounted read only; or the
user has reached their quota for the file system.
* The directory in which the core dump file is to be created does
not exist.
* RLIMIT_CORE or RLIMIT_FSIZE resource limits for a process are
set to zero (see getrlimit(2)).
* The binary being executed by the process does not have read per‐
mission enabled.
* The process is executing a set-user-ID (set-group-ID) program
that is owned by a user (group) other than the real user (group)
ID of the process. (However, see the description of the
prctl(2) PR_SET_DUMPABLE operation, and the description of the
/proc/sys/fs/suid_dumpable file in proc(5).)
My patch doesn't address any of these, and should be ignored.
Ether Apport should be updated to conform to these cases, or the core(5)
man page should be updated to note Apport's behavior.
** Summary changed:
- Apport doesn't remove pre-existing core files
+ Apport doesn't conform to core(5)
** Attachment removed: "Update apport to remove pre-existing core files"
http://launchpadlibrarian.net/17035692/apport-gcc.patch
--
Apport doesn't conform to core(5)
https://bugs.launchpad.net/bugs/160999
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
