[PATCH 3/9] binfmt_elf_fdpic: don't use __... uaccess primitives

From: Al Viro
Date: Fri May 29 2020 - 19:27:32 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf_fdpic.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 240f66663543..ab6fb117b33c 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -537,7 +537,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
platform_len = strlen(k_platform) + 1;
sp -= platform_len;
u_platform = (char __user *) sp;
- if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
+ if (copy_to_user(u_platform, k_platform, platform_len) != 0)
return -EFAULT;
}

@@ -552,7 +552,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
platform_len = strlen(k_base_platform) + 1;
sp -= platform_len;
u_base_platform = (char __user *) sp;
- if (__copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
+ if (copy_to_user(u_base_platform, k_base_platform, platform_len) != 0)
return -EFAULT;
}

@@ -604,11 +604,13 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
/* put the ELF interpreter info on the stack */
#define NEW_AUX_ENT(id, val) \
do { \
- struct { unsigned long _id, _val; } __user *ent; \
+ struct { unsigned long _id, _val; } __user *ent, v; \
\
ent = (void __user *) csp; \
- __put_user((id), &ent[nr]._id); \
- __put_user((val), &ent[nr]._val); \
+ v._id = (id); \
+ v._val = (val); \
+ if (copy_to_user(ent + nr, &v)) \
+ return -EFAULT; \
nr++; \
} while (0)

@@ -675,7 +677,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,

/* stack argc */
csp -= sizeof(unsigned long);
- __put_user(bprm->argc, (unsigned long __user *) csp);
+ if (put_user(bprm->argc, (unsigned long __user *) csp))
+ return -EFAULT;

BUG_ON(csp != sp);

@@ -689,25 +692,29 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,

p = (char __user *) current->mm->arg_start;
for (loop = bprm->argc; loop > 0; loop--) {
- __put_user((elf_caddr_t) p, argv++);
+ if (put_user((elf_caddr_t) p, argv++))
+ return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
- __put_user(NULL, argv);
+ if (put_user(NULL, argv))
+ return -EFAULT;
current->mm->arg_end = (unsigned long) p;

/* fill in the envv[] array */
current->mm->env_start = (unsigned long) p;
for (loop = bprm->envc; loop > 0; loop--) {
- __put_user((elf_caddr_t)(unsigned long) p, envp++);
+ if (put_user((elf_caddr_t)(unsigned long) p, envp++))
+ return -EFAULT;
len = strnlen_user(p, MAX_ARG_STRLEN);
if (!len || len > MAX_ARG_STRLEN)
return -EINVAL;
p += len;
}
- __put_user(NULL, envp);
+ if (put_user(NULL, envp))
+ return -EFAULT;
current->mm->env_end = (unsigned long) p;

mm->start_stack = (unsigned long) sp;
@@ -849,8 +856,8 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,

tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
dyn = (Elf32_Dyn __user *)params->dynamic_addr;
- __get_user(d_tag, &dyn[tmp - 1].d_tag);
- if (d_tag != 0)
+ if (get_user(d_tag, &dyn[tmp - 1].d_tag) ||
+ d_tag != 0)
goto dynamic_error;
break;
}
--
2.11.0