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mm: apply_to_pte_range warn and fail if a large pte is encountered

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apply_to_pte_range might mistake a large pte for bad, or treat it as a
page table, resulting in a crash or corruption.  Add a test to warn and
return error if large entries are found.

Link: https://lkml.kernel.org/r/20210317062402.533919-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ding Tianhong <dingtianhong@huawei.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nicholas Piggin 2021-04-29 22:58:16 -07:00 • committed by Linus Torvalds
parent c0eb315ad9
commit 0c95cba492
1 changed files with 49 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

66
mm/memory.c
View file

@ -2457,13 +2457,21 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
} }
do { do {
next = pmd_addr_end(addr, end); next = pmd_addr_end(addr, end);
if (create || !pmd_none_or_clear_bad(pmd)) { if (pmd_none(*pmd) && !create)
err = apply_to_pte_range(mm, pmd, addr, next, fn, data, continue;
create, mask); if (WARN_ON_ONCE(pmd_leaf(*pmd)))
if (err) return -EINVAL;
break; if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) {
if (!create)
continue;
pmd_clear_bad(pmd);
} }
err = apply_to_pte_range(mm, pmd, addr, next,
fn, data, create, mask);
if (err)
break;
} while (pmd++, addr = next, addr != end); } while (pmd++, addr = next, addr != end);
return err; return err;
} }
@ -2485,13 +2493,21 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
} }
do { do {
next = pud_addr_end(addr, end); next = pud_addr_end(addr, end);
if (create || !pud_none_or_clear_bad(pud)) { if (pud_none(*pud) && !create)
err = apply_to_pmd_range(mm, pud, addr, next, fn, data, continue;
create, mask); if (WARN_ON_ONCE(pud_leaf(*pud)))
if (err) return -EINVAL;
break; if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) {
if (!create)
continue;
pud_clear_bad(pud);
} }
err = apply_to_pmd_range(mm, pud, addr, next,
fn, data, create, mask);
if (err)
break;
} while (pud++, addr = next, addr != end); } while (pud++, addr = next, addr != end);
return err; return err;
} }
@ -2513,13 +2529,21 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
} }
do { do {
next = p4d_addr_end(addr, end); next = p4d_addr_end(addr, end);
if (create || !p4d_none_or_clear_bad(p4d)) { if (p4d_none(*p4d) && !create)
err = apply_to_pud_range(mm, p4d, addr, next, fn, data, continue;
create, mask); if (WARN_ON_ONCE(p4d_leaf(*p4d)))
if (err) return -EINVAL;
break; if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) {
if (!create)
continue;
p4d_clear_bad(p4d);
} }
err = apply_to_pud_range(mm, p4d, addr, next,
fn, data, create, mask);
if (err)
break;
} while (p4d++, addr = next, addr != end); } while (p4d++, addr = next, addr != end);
return err; return err;
} }
@ -2539,9 +2563,17 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
pgd = pgd_offset(mm, addr); pgd = pgd_offset(mm, addr);
do { do {
next = pgd_addr_end(addr, end); next = pgd_addr_end(addr, end);
if (!create && pgd_none_or_clear_bad(pgd)) if (pgd_none(*pgd) && !create)
continue; continue;
err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask); if (WARN_ON_ONCE(pgd_leaf(*pgd)))
return -EINVAL;
if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) {
if (!create)
continue;
pgd_clear_bad(pgd);
}
err = apply_to_p4d_range(mm, pgd, addr, next,
fn, data, create, &mask);
if (err) if (err)
break; break;
} while (pgd++, addr = next, addr != end); } while (pgd++, addr = next, addr != end);