@@ -2352,16 +2352,21 @@ static int
kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt,
unsigned long *addrs)
{
- unsigned long addr, size;
+ unsigned long addr;
+ size_t sym_size;
+ u32 size, elem_size;
const char __user **syms;
+ compat_uptr_t __user *compat_syms;
int err = -ENOMEM;
unsigned int i;
char *func;
- if (check_mul_overflow(cnt, sizeof(*syms), &size))
+ elem_size = in_compat_syscall() ? sizeof(*compat_syms) : sizeof(*syms);
+ if (check_mul_overflow(cnt, elem_size, &size))
return -EOVERFLOW;
- size = cnt * sizeof(*syms);
+ size = cnt * elem_size;
syms = kvzalloc(size, GFP_KERNEL);
+ compat_syms = (void *)syms;
if (!syms)
return -ENOMEM;
@@ -2375,7 +2380,10 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt,
}
for (i = 0; i < cnt; i++) {
- err = strncpy_from_user(func, syms[i], KSYM_NAME_LEN);
+ const char __user *ufunc = in_compat_syscall()
+ ? (char __user *)(uintptr_t)compat_syms[i]
+ : syms[i];
+ err = strncpy_from_user(func, ufunc, KSYM_NAME_LEN);
if (err == KSYM_NAME_LEN)
err = -E2BIG;
if (err < 0)
@@ -2384,9 +2392,9 @@ kprobe_multi_resolve_syms(const void __user *usyms, u32 cnt,
addr = kallsyms_lookup_name(func);
if (!addr)
goto error;
- if (!kallsyms_lookup_size_offset(addr, &size, NULL))
+ if (!kallsyms_lookup_size_offset(addr, &sym_size, NULL))
goto error;
- addr = ftrace_location_range(addr, addr + size - 1);
+ addr = ftrace_location_range(addr, addr + sym_size - 1);
if (!addr)
goto error;
addrs[i] = addr;
For compat processes, userspace pointer size is different. Since the copied array is iterated anyway, the simplest fix seems to be copy the user-supplied array as-is and the iterate as an array of native or compat pointers, depending on the in_compat_syscall() value. Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link") Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> --- kernel/trace/bpf_trace.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)