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| author | Florian Weimer <fweimer@redhat.com> | 2019-08-28 11:59:45 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2019-08-28 11:59:45 +0200 |
| commit | 61d3db428176d9d0822e4e680305fe34285edff2 (patch) | |
| tree | 22ad4258b0d656bdf5ece29ade65a3e321a9a1b9 /login/Makefile | |
| parent | 3a9d025fdd56f595ef9cb142486da4ee1b75281f (diff) | |
| download | glibc-61d3db428176d9d0822e4e680305fe34285edff2.tar.xz glibc-61d3db428176d9d0822e4e680305fe34285edff2.zip | |
login: pututxline could fail to overwrite existing entries [BZ #24902]
The internal_getut_r function updates the file_offset variable and
therefore must always update last_entry as well.
Previously, if pututxline could not upgrade the read lock to a
write lock, internal_getut_r would update file_offset only,
without updating last_entry, and a subsequent call would not
overwrite the existing utmpx entry at file_offset, instead
creating a new entry. This has been observed to cause unbounded
file growth in high-load situations.
This commit removes the buffer argument to internal_getut_r and
updates the last_entry variable directly, along with file_offset.
Initially reported and fixed by Ondřej Lysoněk.
Reviewed-by: Gabriel F. T. Gomes <gabrielftg@linux.ibm.com>
Diffstat (limited to 'login/Makefile')
| -rw-r--r-- | login/Makefile | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/login/Makefile b/login/Makefile index f9c4264087..93a3c8edf2 100644 --- a/login/Makefile +++ b/login/Makefile @@ -43,7 +43,8 @@ endif subdir-dirs = programs vpath %.c programs -tests := tst-utmp tst-utmpx tst-grantpt tst-ptsname tst-getlogin tst-updwtmpx +tests := tst-utmp tst-utmpx tst-grantpt tst-ptsname tst-getlogin tst-updwtmpx \ + tst-pututxline-lockfail # Build the -lutil library with these extra functions. extra-libs := libutil @@ -71,3 +72,5 @@ endif $(inst_libexecdir)/pt_chown: $(objpfx)pt_chown $(+force) $(make-target-directory) -$(INSTALL_PROGRAM) -m 4755 -o root $< $@ + +$(objpfx)tst-pututxline-lockfail: $(shared-thread-library) |