Reland "[ASan] Do not misrepresent high value address dereferences as… #150
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… null dereferences" Updated: Removed offending TODO comment. Dereferences with addresses above the 48-bit hardware addressable range produce "invalid instruction" (instead of "invalid access") hardware exceptions (there is no hardware address decoding logic for those bits), and the address provided by this exception is the address of the instruction (not the faulting address). The kernel maps the "invalid instruction" to SEGV, but fails to provide the real fault address. Because of this ASan lies and says that those cases are null dereferences. This downgrades the severity of a found bug in terms of security. In the ASan signal handler, we can not provide the real faulting address, but at least we can try not to lie. rdar://50366151 Reviewed By: vitalybuka Differential Revision: https://reviews.llvm.org/D68676 > llvm-svn: 374265 llvm-svn: 374384 (cherry picked from commit 99c9d7b)
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@swift-ci Please test |
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… null dereferences"
Updated: Removed offending TODO comment.
Dereferences with addresses above the 48-bit hardware addressable range
produce "invalid instruction" (instead of "invalid access") hardware
exceptions (there is no hardware address decoding logic for those bits),
and the address provided by this exception is the address of the
instruction (not the faulting address). The kernel maps the "invalid
instruction" to SEGV, but fails to provide the real fault address.
Because of this ASan lies and says that those cases are null
dereferences. This downgrades the severity of a found bug in terms of
security. In the ASan signal handler, we can not provide the real
faulting address, but at least we can try not to lie.
rdar://50366151
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D68676
llvm-svn: 374384
(cherry picked from commit 99c9d7b)