tree 410a27383126be084e4b92a6ec3d9621d8663d99
parent 9fd98a6354105dd67b648b48dba238f4c3e3d564
author Szabolcs Nagy <nsz@port70.net> 1558026933 +0000
committer Rich Felker <dalias@aerifal.cx> 1558051976 -0400

fix static tls offsets of shared libs on TLS_ABOVE_TP targets

tls_offset should always point to the end of the allocated static tls
area, but this was not handled correctly on "tls variant 1" targets
in the dynamic linker:

after application tls was allocated, tls_offset was aligned up,
potentially wasting tls space. (alignment may be needed at the
begining of the tls area, not at the end, but that will be fixed
separately as it is unlikely to affect real binaries.)

when static tls was allocated for a shared library, tls_offset was
only updated with the size of the tls segment which does not include
alignment gaps, which can easily happen if the tls size update for
one library leaves tls_offset misaligned for the next one. this can
cause oob access in __copy_tls or arbitrary breakage at tls access.
(the issue was observed on aarch64 with rust binaries)