From 222ca305c9fd39e5ed8104da25c09b2b79a516a8 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 10 Feb 2022 16:24:30 +0100 Subject: uaccess: fix integer overflow on access_ok() Three architectures check the end of a user access against the address limit without taking a possible overflow into account. Passing a negative length or another overflow in here returns success when it should not. Use the most common correct implementation here, which optimizes for a constant 'size' argument, and turns the common case into a single comparison. Cc: stable@vger.kernel.org Fixes: da551281947c ("csky: User access") Fixes: f663b60f5215 ("microblaze: Fix uaccess_ok macro") Fixes: 7567746e1c0d ("Hexagon: Add user access functions") Reported-by: David Laight Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann --- arch/microblaze/include/asm/uaccess.h | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index d2a8ef9f8978..5b6e0e7788f4 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -39,24 +39,13 @@ # define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -static inline int access_ok(const void __user *addr, unsigned long size) +static inline int __access_ok(unsigned long addr, unsigned long size) { - if (!size) - goto ok; + unsigned long limit = user_addr_max(); - if ((get_fs().seg < ((unsigned long)addr)) || - (get_fs().seg < ((unsigned long)addr + size - 1))) { - pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n", - (__force u32)addr, (u32)size, - (u32)get_fs().seg); - return 0; - } -ok: - pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n", - (__force u32)addr, (u32)size, - (u32)get_fs().seg); - return 1; + return (size <= limit) && (addr <= (limit - size)); } +#define access_ok(addr, size) __access_ok((unsigned long)addr, size) # define __FIXUP_SECTION ".section .fixup,\"ax\"\n" # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" -- cgit v1.2.3 From a97b693c3712f040c5802f32b2d685352e08cefa Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 15 Feb 2022 15:37:37 +0100 Subject: uaccess: fix nios2 and microblaze get_user_8() These two architectures implement 8-byte get_user() through a memcpy() into a four-byte variable, which won't fit. Use a temporary 64-bit variable instead here, and use a double cast the way that risc-v and openrisc do to avoid compile-time warnings. Fixes: 6a090e97972d ("arch/microblaze: support get_user() of size 8 bytes") Fixes: 5ccc6af5e88e ("nios2: Memory management") Reviewed-by: Christoph Hellwig Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann --- arch/microblaze/include/asm/uaccess.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index 5b6e0e7788f4..3fe96979d2c6 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -130,27 +130,27 @@ extern long __user_bad(void); #define __get_user(x, ptr) \ ({ \ - unsigned long __gu_val = 0; \ long __gu_err; \ switch (sizeof(*(ptr))) { \ case 1: \ - __get_user_asm("lbu", (ptr), __gu_val, __gu_err); \ + __get_user_asm("lbu", (ptr), x, __gu_err); \ break; \ case 2: \ - __get_user_asm("lhu", (ptr), __gu_val, __gu_err); \ + __get_user_asm("lhu", (ptr), x, __gu_err); \ break; \ case 4: \ - __get_user_asm("lw", (ptr), __gu_val, __gu_err); \ + __get_user_asm("lw", (ptr), x, __gu_err); \ break; \ - case 8: \ - __gu_err = __copy_from_user(&__gu_val, ptr, 8); \ - if (__gu_err) \ - __gu_err = -EFAULT; \ + case 8: { \ + __u64 __x = 0; \ + __gu_err = raw_copy_from_user(&__x, ptr, 8) ? \ + -EFAULT : 0; \ + (x) = (typeof(x))(typeof((x) - (x)))__x; \ break; \ + } \ default: \ /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\ } \ - x = (__force __typeof__(*(ptr))) __gu_val; \ __gu_err; \ }) -- cgit v1.2.3 From 12700c17fc286149324f92d6d380bc48e43f253d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 15 Feb 2022 17:55:04 +0100 Subject: uaccess: generalize access_ok() There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig Acked-by: Mark Rutland [arm64, asm-generic] Acked-by: Geert Uytterhoeven Acked-by: Stafford Horne Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann --- arch/microblaze/include/asm/uaccess.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index 3fe96979d2c6..bf9b7657a65a 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -39,13 +39,7 @@ # define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -static inline int __access_ok(unsigned long addr, unsigned long size) -{ - unsigned long limit = user_addr_max(); - - return (size <= limit) && (addr <= (limit - size)); -} -#define access_ok(addr, size) __access_ok((unsigned long)addr, size) +#include # define __FIXUP_SECTION ".section .fixup,\"ax\"\n" # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" -- cgit v1.2.3 From 967747bbc084b93b54e66f9047d342232314cd25 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 11 Feb 2022 21:42:45 +0100 Subject: uaccess: remove CONFIG_SET_FS There are no remaining callers of set_fs(), so CONFIG_SET_FS can be removed globally, along with the thread_info field and any references to it. This turns access_ok() into a cheaper check against TASK_SIZE_MAX. As CONFIG_SET_FS is now gone, drop all remaining references to set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel(). Acked-by: Sam Ravnborg # for sparc32 changes Acked-by: "Eric W. Biederman" Tested-by: Sergey Matyukevich # for arc changes Acked-by: Stafford Horne # [openrisc, asm-generic] Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann --- arch/microblaze/Kconfig | 1 - arch/microblaze/include/asm/thread_info.h | 6 ------ arch/microblaze/include/asm/uaccess.h | 24 ------------------------ arch/microblaze/kernel/asm-offsets.c | 1 - arch/microblaze/kernel/process.c | 1 - 5 files changed, 33 deletions(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig index 59798e43cdb0..1fb1cec087b7 100644 --- a/arch/microblaze/Kconfig +++ b/arch/microblaze/Kconfig @@ -42,7 +42,6 @@ config MICROBLAZE select CPU_NO_EFFICIENT_FFS select MMU_GATHER_NO_RANGE select SPARSE_IRQ - select SET_FS select ZONE_DMA select TRACE_IRQFLAGS_SUPPORT diff --git a/arch/microblaze/include/asm/thread_info.h b/arch/microblaze/include/asm/thread_info.h index 44f5ca331862..a0ddd2a36fb9 100644 --- a/arch/microblaze/include/asm/thread_info.h +++ b/arch/microblaze/include/asm/thread_info.h @@ -56,17 +56,12 @@ struct cpu_context { __u32 fsr; }; -typedef struct { - unsigned long seg; -} mm_segment_t; - struct thread_info { struct task_struct *task; /* main task structure */ unsigned long flags; /* low level flags */ unsigned long status; /* thread-synchronous flags */ __u32 cpu; /* current CPU */ __s32 preempt_count; /* 0 => preemptable,< 0 => BUG*/ - mm_segment_t addr_limit; /* thread address space */ struct cpu_context cpu_context; }; @@ -80,7 +75,6 @@ struct thread_info { .flags = 0, \ .cpu = 0, \ .preempt_count = INIT_PREEMPT_COUNT, \ - .addr_limit = KERNEL_DS, \ } /* how to get the thread information struct from C */ diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index bf9b7657a65a..3aab2f17e046 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -15,30 +15,6 @@ #include #include #include - -/* - * On Microblaze the fs value is actually the top of the corresponding - * address space. - * - * The fs value determines whether argument validity checking should be - * performed or not. If get_fs() == USER_DS, checking is performed, with - * get_fs() == KERNEL_DS, checking is bypassed. - * - * For historical reasons, these macros are grossly misnamed. - * - * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal. - */ -# define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) - -# define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF) -# define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) - -# define get_fs() (current_thread_info()->addr_limit) -# define set_fs(val) (current_thread_info()->addr_limit = (val)) -# define user_addr_max() get_fs().seg - -# define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - #include # define __FIXUP_SECTION ".section .fixup,\"ax\"\n" diff --git a/arch/microblaze/kernel/asm-offsets.c b/arch/microblaze/kernel/asm-offsets.c index b77dd188dec4..47ee409508b1 100644 --- a/arch/microblaze/kernel/asm-offsets.c +++ b/arch/microblaze/kernel/asm-offsets.c @@ -86,7 +86,6 @@ int main(int argc, char *argv[]) /* struct thread_info */ DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); - DEFINE(TI_ADDR_LIMIT, offsetof(struct thread_info, addr_limit)); DEFINE(TI_CPU_CONTEXT, offsetof(struct thread_info, cpu_context)); DEFINE(TI_PREEMPT_COUNT, offsetof(struct thread_info, preempt_count)); BLANK(); diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c index 5e2b91c1e8ce..1b944d319d73 100644 --- a/arch/microblaze/kernel/process.c +++ b/arch/microblaze/kernel/process.c @@ -18,7 +18,6 @@ #include #include #include -#include /* for USER_DS macros */ #include void show_regs(struct pt_regs *regs) -- cgit v1.2.3