Hi Samuel, On 15/08/2024 02:57, Samuel Holland wrote:
raw_copy_{to,from}_user() do not call access_ok(), so this code allowed userspace to access any virtual memory address. Cc: stable@xxxxxxxxxxxxxxx Fixes: 7c83232161f6 ("riscv: add support for misaligned trap handling in S-mode") Fixes: 441381506ba7 ("riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code") Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx> --- arch/riscv/kernel/traps_misaligned.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index b62d5a2f4541..1a76f99ff185 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -417,7 +417,7 @@ int handle_misaligned_load(struct pt_regs *regs)val.data_u64 = 0;if (user_mode(regs)) { - if (raw_copy_from_user(&val, (u8 __user *)addr, len)) + if (copy_from_user(&val, (u8 __user *)addr, len)) return -1; } else { memcpy(&val, (u8 *)addr, len); @@ -515,7 +515,7 @@ int handle_misaligned_store(struct pt_regs *regs) return -EOPNOTSUPP;if (user_mode(regs)) {- if (raw_copy_to_user((u8 __user *)addr, &val, len)) + if (copy_to_user((u8 __user *)addr, &val, len)) return -1; } else { memcpy((u8 *)addr, &val, len);
We could even do the access_ok() *before* even calling handle_misaligned_load() in do_trap_load_misaligned() to back off earlier. But unless you think it is important, I'm fine with this patch, it's on my list for -fixes!
Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx> Thanks, Alex
