From 836b2fe544a5e9b5ce116622cb36fba33838c6fd Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 01:33:23 -0700 Subject: selftests/bpf: Check that JMP32 pointer vs zero jumps are not predicted Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which the verifier used to skip, contains an out of bounds map value access, hence w/o the previous patch the program is accepted. See previous patch for detailed description. Reported-by: Nicholas Carlini Suggested-by: Nicholas Carlini Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- lib/cmpdi2.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 lib/cmpdi2.c (limited to 'lib/cmpdi2.c') diff --git a/lib/cmpdi2.c b/lib/cmpdi2.c new file mode 100644 index 000000000..f7cebd52b --- /dev/null +++ b/lib/cmpdi2.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + */ + +#include + +#include + +word_type notrace __cmpdi2(long long a, long long b) +{ + const DWunion au = { + .ll = a + }; + const DWunion bu = { + .ll = b + }; + + if (au.s.high < bu.s.high) + return 0; + else if (au.s.high > bu.s.high) + return 2; + + if ((unsigned int) au.s.low < (unsigned int) bu.s.low) + return 0; + else if ((unsigned int) au.s.low > (unsigned int) bu.s.low) + return 2; + + return 1; +} +EXPORT_SYMBOL(__cmpdi2); -- cgit v1.3.1