| Message ID | 20240815005714.1163136-1-samuel.holland@sifive.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | b686ecdeacf6658e1348c1a32a08e2e72f7c0f00 |
| Headers | show |
| Series | riscv: misaligned: Restrict user access to kernel memory | expand |
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@vger.kernel.org > 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@sifive.com> > --- > > 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@rivosinc.com> Thanks, Alex
Hello: This patch was applied to riscv/linux.git (fixes) by Palmer Dabbelt <palmer@rivosinc.com>: On Wed, 14 Aug 2024 17:57:03 -0700 you wrote: > raw_copy_{to,from}_user() do not call access_ok(), so this code allowed > userspace to access any virtual memory address. > > Cc: stable@vger.kernel.org > 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@sifive.com> > > [...] Here is the summary with links: - riscv: misaligned: Restrict user access to kernel memory https://git.kernel.org/riscv/c/b686ecdeacf6 You are awesome, thank you!
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);
raw_copy_{to,from}_user() do not call access_ok(), so this code allowed userspace to access any virtual memory address. Cc: stable@vger.kernel.org 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@sifive.com> --- arch/riscv/kernel/traps_misaligned.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)