Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] The checksum calculation for anonymous constants does not align the relocation addend, potentially reading past the end of the constant and out-of-bounds of the section. --
commit 40a0e3ccdee64d957ccae4cb27dbc7318ac09355 Author: Josh Poimboeuf <[email protected]> objtool/klp: Fix checksums for constant pool references This commit addresses false positive changed functions in livepatches by including the underlying data of anonymous constant pool references in the objtool checksum calculation, rather than relying on arbitrary symbol names. > diff --git a/tools/objtool/klp-checksum.c b/tools/objtool/klp-checksum.c > index b8e47f28997e9..ebe25f9c5260a 100644 > --- a/tools/objtool/klp-checksum.c > +++ b/tools/objtool/klp-checksum.c [ ... ] > @@ -129,6 +142,14 @@ static void checksum_update_insn(struct objtool_file > *file, struct symbol *func, > goto alts; > } > > + if (is_anonymous_const_data(sym)) { > + void *cst; > + > + cst = sym->sec->data->d_buf + sym->offset + offset; > + __checksum_update_insn(func, insn, cst, > sym->sec->sh.sh_entsize); [Severity: Medium] Could this result in an out-of-bounds read if the relocation addend is unaligned? In checksum_update_insn(), the code calculates the cst pointer by adding the potentially unaligned offset to the symbol base, but then unconditionally hashes a full sym->sec->sh.sh_entsize bytes. If the compiler emits a relocation to a constant pool section with an unaligned addend (for example, when an instruction accesses a sub-element of a 16-byte constant), reading a full sh_entsize bytes from a mid-constant offset could cross the section buffer boundary if this constant is at the end of the section. Can this lead to non-deterministic checksums by incorporating unrelated memory into the hash, or potentially cause a segfault during the kernel build? > + goto alts; > + } > + > if (is_sec_sym(sym)) { > sym = find_symbol_containing(reloc->sym->sec, offset); > if (!sym) -- Sashiko AI review ยท https://sashiko.dev/#/patchset/f3a9e74ceebc6475ce94bcfe985401140857814a.1787939301.git.jpoim...@kernel.org?part=1
