Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH 2/2] x86: fix __user annotations | Date | Mon, 1 Apr 2019 14:37:23 +0000 |
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From: Jann Horn > Sent: 28 March 2019 21:23 > Fix __user annotations in various places across the x86 tree: > ... > - generic_load_microcode() deals with a pointer that can be either a > kernel pointer or a user pointer; change the code to pass it around as > a __user pointer, and add explicit casts to convert between __user and > __kernel ... > -static int get_ucode_fw(void *to, const void *from, size_t n) > +static int get_ucode_fw(void *to, const void __user *from, size_t n) > { > - memcpy(to, from, n); > + /* cast paired with request_microcode_fw() */ > + memcpy(to, (const void __force *)from, n); > return 0; > } > > @@ -993,7 +996,8 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device, > return UCODE_NFOUND; > } > > - ret = generic_load_microcode(cpu, (void *)firmware->data, > + /* cast paired with get_ucode_fw() */ > + ret = generic_load_microcode(cpu, (void __force __user *)firmware->data, > firmware->size, &get_ucode_fw); > > release_firmware(firmware); > @@ -1001,7 +1005,7 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device, > return ret; > } > > -static int get_ucode_user(void *to, const void *from, size_t n) > +static int get_ucode_user(void *to, const void __user *from, size_t n) > { > return copy_from_user(to, from, n); > } > @@ -1012,7 +1016,7 @@ request_microcode_user(int cpu, const void __user *buf, size_t size) > if (is_blacklisted(cpu)) > return UCODE_NFOUND; > > - return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user); > + return generic_load_microcode(cpu, buf, size, &get_ucode_user);
That is all an 'accident waiting to happen' ...
David
- Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
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