exec: Merge install_exec_creds into setup_new_exec

The two functions are now always called one right after the
other so merge them together to make future maintenance easier.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2020-05-03 06:48:17 -05:00
parent 1507b7a30a
commit 96ecee29b0
8 changed files with 27 additions and 37 deletions

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@ -140,7 +140,6 @@ static int load_aout_binary(struct linux_binprm *bprm)
set_personality_ia32(false);
setup_new_exec(bprm);
install_exec_creds(bprm);
regs->cs = __USER32_CS;
regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 =

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@ -162,7 +162,6 @@ static int load_aout_binary(struct linux_binprm * bprm)
set_personality(PER_LINUX);
#endif
setup_new_exec(bprm);
install_exec_creds(bprm);
current->mm->end_code = ex.a_text +
(current->mm->start_code = N_TXTADDR(ex));

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@ -858,7 +858,6 @@ out_free_interp:
current->flags |= PF_RANDOMIZE;
setup_new_exec(bprm);
install_exec_creds(bprm);
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */

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@ -353,7 +353,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
current->personality |= READ_IMPLIES_EXEC;
setup_new_exec(bprm);
install_exec_creds(bprm);
set_binfmt(&elf_fdpic_format);

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@ -541,7 +541,6 @@ static int load_flat_file(struct linux_binprm *bprm,
/* OK, This is the point of no return */
set_personality(PER_LINUX_32BIT);
setup_new_exec(bprm);
install_exec_creds(bprm);
}
/*

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@ -1443,6 +1443,31 @@ void setup_new_exec(struct linux_binprm * bprm)
group */
WRITE_ONCE(current->self_exec_id, current->self_exec_id + 1);
flush_signal_handlers(current, 0);
/*
* install the new credentials for this executable
*/
security_bprm_committing_creds(bprm);
commit_creds(bprm->cred);
bprm->cred = NULL;
/*
* Disable monitoring for regular users
* when executing setuid binaries. Must
* wait until new credentials are committed
* by commit_creds() above
*/
if (get_dumpable(current->mm) != SUID_DUMP_USER)
perf_event_exit_task(current);
/*
* cred_guard_mutex must be held at least to this point to prevent
* ptrace_attach() from altering our determination of the task's
* credentials; any time after this it may be unlocked.
*/
security_bprm_committed_creds(bprm);
mutex_unlock(&current->signal->exec_update_mutex);
mutex_unlock(&current->signal->cred_guard_mutex);
}
EXPORT_SYMBOL(setup_new_exec);
@ -1458,7 +1483,7 @@ EXPORT_SYMBOL(finalize_exec);
/*
* Prepare credentials and lock ->cred_guard_mutex.
* install_exec_creds() commits the new creds and drops the lock.
* setup_new_exec() commits the new creds and drops the lock.
* Or, if exec fails before, free_bprm() should release ->cred and
* and unlock.
*/
@ -1504,35 +1529,6 @@ int bprm_change_interp(const char *interp, struct linux_binprm *bprm)
}
EXPORT_SYMBOL(bprm_change_interp);
/*
* install the new credentials for this executable
*/
void install_exec_creds(struct linux_binprm *bprm)
{
security_bprm_committing_creds(bprm);
commit_creds(bprm->cred);
bprm->cred = NULL;
/*
* Disable monitoring for regular users
* when executing setuid binaries. Must
* wait until new credentials are committed
* by commit_creds() above
*/
if (get_dumpable(current->mm) != SUID_DUMP_USER)
perf_event_exit_task(current);
/*
* cred_guard_mutex must be held at least to this point to prevent
* ptrace_attach() from altering our determination of the task's
* credentials; any time after this it may be unlocked.
*/
security_bprm_committed_creds(bprm);
mutex_unlock(&current->signal->exec_update_mutex);
mutex_unlock(&current->signal->cred_guard_mutex);
}
EXPORT_SYMBOL(install_exec_creds);
/*
* determine how safe it is to execute the proposed program
* - the caller must hold ->cred_guard_mutex to protect against

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@ -145,7 +145,6 @@ extern int transfer_args_to_stack(struct linux_binprm *bprm,
extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm);
extern int copy_strings_kernel(int argc, const char *const *argv,
struct linux_binprm *bprm);
extern void install_exec_creds(struct linux_binprm *bprm);
extern void set_binfmt(struct linux_binfmt *new);
extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);

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@ -12217,7 +12217,7 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
* When a child task exits, feed back event values to parent events.
*
* Can be called with exec_update_mutex held when called from
* install_exec_creds().
* setup_new_exec().
*/
void perf_event_exit_task(struct task_struct *child)
{