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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2020-01-14 08:13:09 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-23 21:31:13 +1100 |
| commit | d80ae83f1f932ab7af47b54d0d3bef4f4dba489f (patch) | |
| tree | 3d96050c68ce4b2c4965e4e60e76e38224b4977f | |
| parent | e26ad936dd89d79f66c2b567f700e0c2a7103070 (diff) | |
| download | linux-d80ae83f1f932ab7af47b54d0d3bef4f4dba489f.tar.bz2 | |
powerpc/ptdump: Fix W+X verification
Verification cannot rely on simple bit checking because on some
platforms PAGE_RW is 0, checking that a page is not W means
checking that PAGE_RO is set instead of checking that PAGE_RW
is not set.
Use pte helpers instead of checking bits.
Fixes: 453d87f6a8ae ("powerpc/mm: Warn if W+X pages found on boot")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0d894839fdbb19070f0e1e4140363be4f2bb62fc.1578989540.git.christophe.leroy@c-s.fr
| -rw-r--r-- | arch/powerpc/mm/ptdump/ptdump.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index 4af0d5d9589e..206156255247 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -175,10 +175,12 @@ static void dump_addr(struct pg_state *st, unsigned long addr) static void note_prot_wx(struct pg_state *st, unsigned long addr) { + pte_t pte = __pte(st->current_flags); + if (!IS_ENABLED(CONFIG_PPC_DEBUG_WX) || !st->check_wx) return; - if (!((st->current_flags & pgprot_val(PAGE_KERNEL_X)) == pgprot_val(PAGE_KERNEL_X))) + if (!pte_write(pte) || !pte_exec(pte)) return; WARN_ONCE(1, "powerpc/mm: Found insecure W+X mapping at address %p/%pS\n", |