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author | Florian Weimer <fweimer@redhat.com> | 2019-08-28 11:59:45 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2019-08-28 11:59:45 +0200 |
commit | 61d3db428176d9d0822e4e680305fe34285edff2 (patch) | |
tree | 22ad4258b0d656bdf5ece29ade65a3e321a9a1b9 /nptl/forward.c | |
parent | 3a9d025fdd56f595ef9cb142486da4ee1b75281f (diff) | |
download | glibc-61d3db428176d9d0822e4e680305fe34285edff2.tar.gz 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 'nptl/forward.c')
0 files changed, 0 insertions, 0 deletions