Commit 812cb212 authored May 31, 2022 by Celeste Liu Committed by Greg Kroah-Hartman Aug 25, 2022

riscv: mmap with PROT_WRITE but no PROT_READ is invalid



[ Upstream commit 2139619bcad7ac44cc8f6f749089120594056613 ]

As mentioned in Table 4.5 in RISC-V spec Volume 2 Section 4.3, write
but not read is "Reserved for future use.". For now, they are not valid.
In the current code, -wx is marked as invalid, but -w- is not marked
as invalid.
This patch refines that judgment.

Reported-by: xctan <xc-tan@outlook.com>
Co-developed-by: dram <dramforever@live.com>
Signed-off-by: dram <dramforever@live.com>
Co-developed-by: Ruizhe Pan <c141028@gmail.com>
Signed-off-by: Ruizhe Pan <c141028@gmail.com>
Signed-off-by: Celeste Liu <coelacanthus@outlook.com>
Link: https://lore.kernel.org/r/PH7PR14MB559464DBDD310E755F5B21E8CEDC9@PH7PR14MB5594.namprd14.prod.outlook.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 1b49707d

arch/riscv/kernel/sys_riscv.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -18,8 +18,7 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len,
		if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
		return -EINVAL;

		if ((prot & PROT_WRITE) && (prot & PROT_EXEC))
		if (unlikely(!(prot & PROT_READ)))
		if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ)))
		return -EINVAL;

		return ksys_mmap_pgoff(addr, len, prot, flags, fd,