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| author | Rich Felker <dalias@aerifal.cx> | 2023-03-20 19:07:54 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2023-03-21 09:11:17 -0400 |
| commit | 3a051769c4a91c3a7d1f1310d888faa4abf363e7 (patch) | |
| tree | 440dfaaaca3c36ade1b998a7585863850358be97 /src/stdio | |
| parent | 0440ed69eac766c712e974358c3e09d63e330f40 (diff) | |
| download | musl-3a051769c4a91c3a7d1f1310d888faa4abf363e7.tar.gz | |
fix (normal, narrow) printf erroneously processing %n after output errors
unlike with wide printf variants, encoding errors are not a vector by
which this bug is reachable, and the out() helper function already
ensured that no further output could be written after an output error,
transient or otherwise. however, the %n specifier could still be
processed after an error, yielding a side effect that wrongly implied
output had succeeded.
due to buffering effects, it's still possible for %n to show output as
having "succeeded", but for it never to appear on the underlying file
due to an error at flush time. this change, however, ensures that
processing of %n does not conflict with any error which has already
been seen.
Diffstat (limited to 'src/stdio')
| -rw-r--r-- | src/stdio/vfprintf.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c index 45557951..2dbdb5e2 100644 --- a/src/stdio/vfprintf.c +++ b/src/stdio/vfprintf.c @@ -530,6 +530,9 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, if (!f) continue; + /* Do not process any new directives once in error state. */ + if (ferror(f)) return -1; + z = buf + sizeof(buf); prefix = "-+ 0X0x"; pl = 0; |