From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net,
hch@lst.de, hpa@zytor.com, linux-mm@kvack.org,
mhiramat@kernel.org, mingo@elte.hu, mm-commits@vger.kernel.org,
svens@linux.ibm.com, tglx@linutronix.de,
torvalds@linux-foundation.org
Subject: [patch 86/93] tracing/kprobes: handle mixed kernel/userspace probes better
Date: Mon, 08 Jun 2020 21:34:44 -0700 [thread overview]
Message-ID: <20200609043444.8qanU5wfk%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200608212922.5b7fa74ca3f4e2444441b7f9@linux-foundation.org>
From: Christoph Hellwig <hch@lst.de>
Subject: tracing/kprobes: handle mixed kernel/userspace probes better
Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe
helpers, rework probes to try a user probe based on the address if the
architecture has a common address space for kernel and userspace.
[svens@linux.ibm.com:use strncpy_from_kernel_nofault() in fetch_store_string()]
Link: http://lkml.kernel.org/r/20200606181903.49384-1-svens@linux.ibm.com
Link: http://lkml.kernel.org/r/20200521152301.2587579-15-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
kernel/trace/trace_kprobe.c | 72 ++++++++++++++++++++--------------
1 file changed, 43 insertions(+), 29 deletions(-)
--- a/kernel/trace/trace_kprobe.c~tracing-kprobes-handle-mixed-kernel-userspace-probes-better
+++ a/kernel/trace/trace_kprobe.c
@@ -1202,35 +1202,41 @@ static const struct file_operations kpro
/* Return the length of string -- including null terminal byte */
static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+ const void __user *uaddr = (__force const void __user *)addr;
+
+ return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
fetch_store_strlen(unsigned long addr)
{
int ret, len = 0;
u8 c;
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if (addr < TASK_SIZE)
+ return fetch_store_strlen_user(addr);
+#endif
+
do {
- ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
+ ret = probe_kernel_read_strict(&c, (u8 *)addr + len, 1);
len++;
} while (c && ret == 0 && len < MAX_STRING_SIZE);
return (ret < 0) ? ret : len;
}
-/* Return the length of string -- including null terminal byte */
-static nokprobe_inline int
-fetch_store_strlen_user(unsigned long addr)
-{
- const void __user *uaddr = (__force const void __user *)addr;
-
- return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
-}
-
/*
- * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
- * length and relative data location.
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
*/
static nokprobe_inline int
-fetch_store_string(unsigned long addr, void *dest, void *base)
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
{
+ const void __user *uaddr = (__force const void __user *)addr;
int maxlen = get_loc_len(*(u32 *)dest);
void *__dest;
long ret;
@@ -1240,11 +1246,7 @@ fetch_store_string(unsigned long addr, v
__dest = get_loc_data(dest, base);
- /*
- * Try to get string again, since the string can be changed while
- * probing.
- */
- ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
+ ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
if (ret >= 0)
*(u32 *)dest = make_data_loc(ret, __dest - base);
@@ -1252,23 +1254,31 @@ fetch_store_string(unsigned long addr, v
}
/*
- * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
- * with max length and relative data location.
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
*/
static nokprobe_inline int
-fetch_store_string_user(unsigned long addr, void *dest, void *base)
+fetch_store_string(unsigned long addr, void *dest, void *base)
{
- const void __user *uaddr = (__force const void __user *)addr;
int maxlen = get_loc_len(*(u32 *)dest);
void *__dest;
long ret;
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if ((unsigned long)addr < TASK_SIZE)
+ return fetch_store_string_user(addr, dest, base);
+#endif
+
if (unlikely(!maxlen))
return -ENOMEM;
__dest = get_loc_data(dest, base);
- ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
+ /*
+ * Try to get string again, since the string can be changed while
+ * probing.
+ */
+ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
if (ret >= 0)
*(u32 *)dest = make_data_loc(ret, __dest - base);
@@ -1276,12 +1286,6 @@ fetch_store_string_user(unsigned long ad
}
static nokprobe_inline int
-probe_mem_read(void *dest, void *src, size_t size)
-{
- return probe_kernel_read(dest, src, size);
-}
-
-static nokprobe_inline int
probe_mem_read_user(void *dest, void *src, size_t size)
{
const void __user *uaddr = (__force const void __user *)src;
@@ -1289,6 +1293,16 @@ probe_mem_read_user(void *dest, void *sr
return probe_user_read(dest, uaddr, size);
}
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if ((unsigned long)src < TASK_SIZE)
+ return probe_mem_read_user(dest, src, size);
+#endif
+ return probe_kernel_read_strict(dest, src, size);
+}
+
/* Note that we don't verify it, since the code does not come from user space */
static int
process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
_
next prev parent reply other threads:[~2020-06-09 4:34 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-09 4:29 incoming Andrew Morton
2020-06-09 4:29 ` [patch 01/93] kallsyms/printk: add loglvl to print_ip_sym() Andrew Morton
2020-06-09 4:30 ` [patch 02/93] alpha: add show_stack_loglvl() Andrew Morton
2020-06-09 4:30 ` [patch 03/93] arc: " Andrew Morton
2020-06-09 4:30 ` [patch 04/93] arm/asm: add loglvl to c_backtrace() Andrew Morton
2020-06-09 4:30 ` [patch 05/93] arm: add loglvl to unwind_backtrace() Andrew Morton
2020-06-09 4:30 ` [patch 06/93] arm: add loglvl to dump_backtrace() Andrew Morton
2020-06-09 4:30 ` [patch 07/93] arm: wire up dump_backtrace_{entry,stm} Andrew Morton
2020-06-09 4:30 ` [patch 08/93] arm: add show_stack_loglvl() Andrew Morton
2020-06-09 4:30 ` [patch 09/93] arm64: add loglvl to dump_backtrace() Andrew Morton
2020-06-09 4:30 ` [patch 10/93] arm64: add show_stack_loglvl() Andrew Morton
2020-06-09 4:30 ` [patch 11/93] c6x: " Andrew Morton
2020-06-09 4:30 ` [patch 12/93] csky: " Andrew Morton
2020-06-09 4:30 ` [patch 13/93] h8300: " Andrew Morton
2020-06-09 4:30 ` [patch 14/93] hexagon: " Andrew Morton
2020-06-09 4:30 ` [patch 15/93] ia64: pass log level as arg into ia64_do_show_stack() Andrew Morton
2020-06-09 4:30 ` [patch 16/93] ia64: add show_stack_loglvl() Andrew Morton
2020-06-09 4:30 ` [patch 17/93] m68k: " Andrew Morton
2020-06-09 4:30 ` [patch 18/93] microblaze: add loglvl to microblaze_unwind_inner() Andrew Morton
2020-06-09 4:30 ` [patch 19/93] microblaze: add loglvl to microblaze_unwind() Andrew Morton
2020-06-09 4:30 ` [patch 20/93] microblaze: add show_stack_loglvl() Andrew Morton
2020-06-09 4:30 ` [patch 21/93] mips: " Andrew Morton
2020-06-09 4:31 ` [patch 22/93] nds32: " Andrew Morton
2020-06-09 4:31 ` [patch 23/93] nios2: " Andrew Morton
2020-06-09 4:31 ` [patch 24/93] openrisc: " Andrew Morton
2020-06-09 4:31 ` [patch 25/93] parisc: " Andrew Morton
2020-06-09 4:31 ` [patch 26/93] powerpc: " Andrew Morton
2020-06-09 4:31 ` [patch 27/93] riscv: " Andrew Morton
2020-06-09 4:31 ` [patch 28/93] s390: " Andrew Morton
2020-06-09 4:31 ` [patch 29/93] sh: add loglvl to dump_mem() Andrew Morton
2020-06-09 4:31 ` [patch 30/93] sh: remove needless printk() Andrew Morton
2020-06-09 4:31 ` [patch 31/93] sh: add loglvl to printk_address() Andrew Morton
2020-06-09 4:31 ` [patch 32/93] sh: add loglvl to show_trace() Andrew Morton
2020-06-09 4:31 ` [patch 33/93] sh: add show_stack_loglvl() Andrew Morton
2020-06-09 4:31 ` [patch 34/93] sparc: " Andrew Morton
2020-06-09 4:31 ` [patch 35/93] um/sysrq: remove needless variable sp Andrew Morton
2020-06-09 4:31 ` [patch 36/93] um: add show_stack_loglvl() Andrew Morton
2020-06-09 4:31 ` [patch 37/93] unicore32: remove unused pmode argument in c_backtrace() Andrew Morton
2020-06-09 4:31 ` [patch 38/93] unicore32: add loglvl to c_backtrace() Andrew Morton
2020-06-09 4:31 ` [patch 39/93] unicore32: add show_stack_loglvl() Andrew Morton
2020-06-09 4:31 ` [patch 40/93] x86: add missing const qualifiers for log_lvl Andrew Morton
2020-06-09 4:32 ` [patch 41/93] x86: add show_stack_loglvl() Andrew Morton
2020-06-09 4:32 ` [patch 42/93] xtensa: add loglvl to show_trace() Andrew Morton
2020-06-09 4:32 ` [patch 43/93] xtensa: add show_stack_loglvl() Andrew Morton
2020-06-09 4:32 ` [patch 44/93] sysrq: use show_stack_loglvl() Andrew Morton
2020-06-09 4:32 ` [patch 45/93] x86/amd_gart: print stacktrace for a leak with KERN_ERR Andrew Morton
2020-06-09 4:32 ` [patch 46/93] power: use show_stack_loglvl() Andrew Morton
2020-06-09 4:32 ` [patch 47/93] kdb: don't play with console_loglevel Andrew Morton
2020-06-09 4:32 ` [patch 48/93] sched: print stack trace with KERN_INFO Andrew Morton
2020-06-09 4:32 ` [patch 49/93] kernel: use show_stack_loglvl() Andrew Morton
2020-06-09 4:32 ` [patch 50/93] kernel: rename show_stack_loglvl() => show_stack() Andrew Morton
2020-06-09 4:32 ` [patch 51/93] mm: don't include asm/pgtable.h if linux/mm.h is already included Andrew Morton
2020-06-09 4:32 ` [patch 52/93] mm: introduce include/linux/pgtable.h Andrew Morton
2020-06-09 4:32 ` [patch 53/93] mm: reorder includes after introduction of linux/pgtable.h Andrew Morton
2020-06-09 4:32 ` [patch 54/93] csky: replace definitions of __pXd_offset() with pXd_index() Andrew Morton
2020-06-09 4:32 ` [patch 55/93] m68k/mm/motorola: move comment about page table allocation funcitons Andrew Morton
2020-06-09 4:32 ` [patch 56/93] m68k/mm: move {cache,nocahe}_page() definitions close to their user Andrew Morton
2020-06-09 4:33 ` [patch 57/93] x86/mm: simplify init_trampoline() and surrounding logic Andrew Morton
2020-06-09 4:33 ` [patch 58/93] mm: pgtable: add shortcuts for accessing kernel PMD and PTE Andrew Morton
2020-06-09 4:33 ` [patch 59/93] mm: consolidate pte_index() and pte_offset_*() definitions Andrew Morton
2020-06-09 4:33 ` [patch 60/93] mmap locking API: initial implementation as rwsem wrappers Andrew Morton
2020-06-09 4:33 ` [patch 61/93] MMU notifier: use the new mmap locking API Andrew Morton
2020-06-09 4:33 ` [patch 62/93] DMA reservations: " Andrew Morton
2020-06-09 4:33 ` [patch 63/93] mmap locking API: use coccinelle to convert mmap_sem rwsem call sites Andrew Morton
2020-06-09 4:33 ` [patch 64/93] mmap locking API: convert mmap_sem call sites missed by coccinelle Andrew Morton
2020-06-09 4:33 ` [patch 65/93] mmap locking API: convert nested write lock sites Andrew Morton
2020-06-09 4:33 ` [patch 66/93] mmap locking API: add mmap_read_trylock_non_owner() Andrew Morton
2020-06-09 4:33 ` [patch 67/93] mmap locking API: add MMAP_LOCK_INITIALIZER Andrew Morton
2020-06-09 4:33 ` [patch 68/93] mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked() Andrew Morton
2020-06-09 4:33 ` [patch 69/93] mmap locking API: rename mmap_sem to mmap_lock Andrew Morton
2020-06-09 4:33 ` [patch 70/93] mmap locking API: convert mmap_sem API comments Andrew Morton
2020-06-09 4:33 ` [patch 71/93] mmap locking API: convert mmap_sem comments Andrew Morton
2020-06-09 4:33 ` [patch 72/93] maccess: unexport probe_kernel_write() Andrew Morton
2020-06-09 4:34 ` [patch 73/93] maccess: remove various unused weak aliases Andrew Morton
2020-06-09 4:34 ` [patch 74/93] maccess: remove duplicate kerneldoc comments Andrew Morton
2020-06-09 4:34 ` [patch 75/93] maccess: clarify " Andrew Morton
2020-06-09 4:34 ` [patch 76/93] maccess: update the top of file comment Andrew Morton
2020-06-09 4:34 ` [patch 77/93] maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault Andrew Morton
2020-06-09 4:34 ` [patch 78/93] maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault Andrew Morton
2020-06-09 4:34 ` [patch 79/93] maccess: rename strnlen_unsafe_user to strnlen_user_nofault Andrew Morton
2020-06-09 4:34 ` [patch 80/93] maccess: remove probe_read_common and probe_write_common Andrew Morton
2020-06-09 4:34 ` [patch 81/93] maccess: unify the probe kernel arch hooks Andrew Morton
2020-06-09 4:34 ` [patch 82/93] bpf: factor out a bpf_trace_copy_string helper Andrew Morton
2020-06-09 4:34 ` [patch 83/93] bpf: handle the compat string in bpf_trace_copy_string better Andrew Morton
2020-06-09 4:34 ` [patch 84/93] bpf:bpf_seq_printf(): handle potentially unsafe format string better Andrew Morton
2020-06-09 4:34 ` [patch 85/93] bpf: rework the compat kernel probe handling Andrew Morton
2020-06-09 4:34 ` Andrew Morton [this message]
2020-06-09 4:34 ` [patch 87/93] maccess: remove strncpy_from_unsafe Andrew Morton
2020-06-09 4:34 ` [patch 88/93] maccess: always use strict semantics for probe_kernel_read Andrew Morton
2020-06-09 4:34 ` [patch 89/93] maccess: move user access routines together Andrew Morton
2020-06-09 4:34 ` [patch 90/93] maccess: allow architectures to provide kernel probing directly Andrew Morton
2020-06-09 4:35 ` [patch 91/93] x86: use non-set_fs based maccess routines Andrew Morton
2020-06-09 18:01 ` Linus Torvalds
2020-06-09 18:06 ` Linus Torvalds
2020-06-10 6:57 ` Christoph Hellwig
2020-06-09 4:35 ` [patch 92/93] maccess: return -ERANGE when probe_kernel_read() fails Andrew Morton
2020-06-09 4:35 ` [patch 93/93] include/linux/cache.h: expand documentation over __read_mostly Andrew Morton
2020-06-17 15:51 ` Christopher Lameter
2020-06-09 5:34 ` mmotm 2020-06-08-22-33 uploaded Andrew Morton
2020-06-09 5:36 ` mmotm 2020-06-08-22-35 uploaded Andrew Morton
2020-06-09 16:58 ` incoming Linus Torvalds
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