src/chgpasswd.c: fix handling of files without trailing newlines #1449
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The chgpasswd command was incorrectly reporting "missing new password" when processing files with a trailing newline. This happened because the code was missing an EOF check. Reproduction steps: $ groupadd tgroup1 $ groupadd tgroup2 $ cat /tmp/test_chgpasswd.txt tgroup1:Secret123 tgroup2:Secret456 $ #The file contains a trailing newline $ chgpasswd < /tmp/test_chgpasswd.txt chgpasswd: line 3: missing new password chgpasswd: error detected, changes ignored Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
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From that reproducer, what I observe is a spurious empty line, not a file without trailing newline. That is, the file ends with 2 new-line characters instead of just 1. |
The proposed patch shouldn't change the behavior of the reproducer you shared, I think. Instead, we should either:
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| if (stpsep(buf, "\n") == NULL) { | ||
| fprintf (stderr, _("%s: line %jd: line too long\n"), | ||
| Prog, line); | ||
| errors = true; | ||
| continue; | ||
| if (feof(stdin) == 0) { | ||
| fprintf (stderr, _("%s: line %jd: line too long\n"), | ||
| Prog, line); | ||
| errors = true; | ||
| continue; | ||
| } | ||
| } |
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Because this code runs only when a newline is not found, it won't change the behavior in the shown reproducer, which has the opposite problem: too many newlines are present.
Do you have a use case for files with blank lines? |
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It turns out that I was creating the file incorrectly 🤦 |
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The chgpasswd command was incorrectly reporting "missing new password" when processing files with a trailing newline. This happened because the code was missing an EOF check.
Reproduction steps:
$ groupadd tgroup1
$ groupadd tgroup2
$ cat /tmp/test_chgpasswd.txt
tgroup1:Secret123
tgroup2:Secret456
$ #The file contains a trailing newline
$ chgpasswd < /tmp/test_chgpasswd.txt
chgpasswd: line 3: missing new password
chgpasswd: error detected, changes ignored