vipw: Use fmkomstemp for temporary file #1485
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alejandro-colomar
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Jan 8, 2026
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Thanks! LGTM.
Reviewed-by: Alejandro Colomar <[email protected]>
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BTW, I guess I should backport this to the stable release 4.19.1. |
Avoid fixed and thus predictable temporary file names. Especially avoid just opening already existing ones. Reviewed-by: Alejandro Colomar <[email protected]> Signed-off-by: Tobias Stoeckmann <[email protected]>
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Since there have been no comments, I'll merge. I'll cherry-pick for the stable release 4.19.1. Thanks! |
alejandro-colomar
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Jan 9, 2026
Regression fixes:
- chpasswd(8):
- Don't reject leading '!' in password hashes or a hash consisting
of "*". These were accidentally rejected in 4.19.0.
See <shadow-maint#1483>
and <shadow-maint#1486>.
Security bug fixes:
- vipw(8):
- Avoid predictable names for temporary files.
This allowed anyone to read the contents of /etc/shadow.
See <shadow-maint#1485>.
Other changes:
- Set SIGCHLD before fork(2). This prevents a possible race
condition, although this is only for making the code more robust;
we believe that the code was correct.
Signed-off-by: Alejandro Colomar <[email protected]>
Draft
alejandro-colomar
added a commit
to alejandro-colomar/shadow
that referenced
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Jan 9, 2026
Regression fixes:
- chpasswd(8):
- Don't reject leading '!' in password hashes or a hash consisting
of "*". These were accidentally rejected in 4.19.0.
See <shadow-maint#1483>
and <shadow-maint#1486>.
Security bug fixes:
- vipw(8):
- Avoid predictable names for temporary files.
This allowed anyone to read the contents of /etc/shadow.
See <shadow-maint#1485>.
Other changes:
- Set SIGCHLD before fork(2). This prevents a possible race
condition, although this is only for making the code more robust;
we believe that the code was correct.
Signed-off-by: Alejandro Colomar <[email protected]>
alejandro-colomar
added a commit
to alejandro-colomar/shadow
that referenced
this pull request
Jan 9, 2026
Regression fixes:
- chpasswd(8):
- Don't reject leading '!' in password hashes or a hash consisting
of "*". These were accidentally rejected in 4.19.0.
See <shadow-maint#1483>
and <shadow-maint#1486>.
Security bug fixes:
- vipw(8):
- Avoid predictable names for temporary files.
This allowed anyone to read the contents of /etc/shadow.
See <shadow-maint#1485>.
Other changes:
- vipw(8):
- Set SIGCHLD before fork(2). This prevents a possible race
condition, although this is only for making the code more robust;
we believe that the code was correct.
Signed-off-by: Alejandro Colomar <[email protected]>
alejandro-colomar
added a commit
to alejandro-colomar/shadow
that referenced
this pull request
Jan 9, 2026
Regression fixes:
- chpasswd(8):
- Don't reject leading '!' in password hashes or a hash consisting
of "*". These were accidentally rejected in 4.19.0.
See <shadow-maint#1483>
and <shadow-maint#1486>.
Security bug fixes:
- vipw(8):
- Avoid predictable names for temporary files.
This allowed anyone to read the contents of /etc/shadow.
See <shadow-maint#1485>.
Other changes:
- vipw(8):
- Set SIGCHLD before fork(2). This prevents a possible race
condition, although this is only for making the code more robust;
we believe that the code was correct.
See <shadow-maint#1484>.
Closes: <shadow-maint#1487>
Signed-off-by: Alejandro Colomar <[email protected]>
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Avoid fixed and thus predictable temporary file names. Especially avoid just opening already existing ones.
Proof of Concept:
You can see the content of /etc/shadow as regular user.