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consolidate BINPRM_FLAGS_ENFORCE_NONDUMP handling

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new helper: would_dump(bprm, file).  Checks if we are allowed to
read the file and if we are not - sets ENFORCE_NODUMP.  Exported,
used in places that previously open-coded the same logics.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-06-19 12:49:47 -04:00
parent 78f32a9b47
commit 1b5d783c94
5 changed files with 15 additions and 9 deletions
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3
fs/binfmt_elf.c
View file

@ -668,8 +668,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
* mm->dumpable = 0 regardless of the interpreter's
* permissions.
*/
if (file_permission(interpreter, MAY_READ) < 0)
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
would_dump(bprm, interpreter);
retval = kernel_read(interpreter, 0, bprm->buf,
BINPRM_BUF_SIZE);

3
fs/binfmt_elf_fdpic.c
View file

@ -245,8 +245,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
* mm->dumpable = 0 regardless of the interpreter's
* permissions.
*/
if (file_permission(interpreter, MAY_READ) < 0)
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
would_dump(bprm, interpreter);
retval = kernel_read(interpreter, 0, bprm->buf,
BINPRM_BUF_SIZE);

3
fs/binfmt_misc.c
View file

@ -149,8 +149,7 @@ static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs)
/* if the binary is not readable than enforce mm->dumpable=0
regardless of the interpreter's permissions */
if (file_permission(bprm->file, MAY_READ))
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
would_dump(bprm, bprm->file);
allow_write_access(bprm->file);
bprm->file = NULL;

14
fs/exec.c
View file

@ -1105,6 +1105,13 @@ int flush_old_exec(struct linux_binprm * bprm)
}
EXPORT_SYMBOL(flush_old_exec);
void would_dump(struct linux_binprm *bprm, struct file *file)
{
if (inode_permission(file->f_path.dentry->d_inode, MAY_READ) < 0)
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
}
EXPORT_SYMBOL(would_dump);
void setup_new_exec(struct linux_binprm * bprm)
{
int i, ch;
@ -1144,9 +1151,10 @@ void setup_new_exec(struct linux_binprm * bprm)
if (bprm->cred->uid != current_euid() ||
bprm->cred->gid != current_egid()) {
current->pdeath_signal = 0;
} else if (file_permission(bprm->file, MAY_READ) ||
bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) {
set_dumpable(current->mm, suid_dumpable);
} else {
would_dump(bprm, bprm->file);
if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
set_dumpable(current->mm, suid_dumpable);
}
/*

1
include/linux/binfmts.h
View file

@ -111,6 +111,7 @@ extern int __must_check remove_arg_zero(struct linux_binprm *);
extern int search_binary_handler(struct linux_binprm *, struct pt_regs *);
extern int flush_old_exec(struct linux_binprm * bprm);
extern void setup_new_exec(struct linux_binprm * bprm);
extern void would_dump(struct linux_binprm *, struct file *);
extern int suid_dumpable;
#define SUID_DUMP_DISABLE 0 /* No setuid dumping */