Unverified Commit 79beea2d authored by Christian Brauner's avatar Christian Brauner
Browse files

fs: remove uselib() system call 

This system call has been deprecated for quite a while now.
Let's try and remove it from the kernel completely.

Link: https://lore.kernel.org/20250415-kanufahren-besten-02ac00e6becd@brauner


Acked-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent d1f48210

arch/m68k/configs/amcore_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ CONFIG_LOCALVERSION="amcore-002" 
CONFIG_DEFAULT_HOSTNAME="amcore"

CONFIG_SYSVIPC=y

# CONFIG_FHANDLE is not set

# CONFIG_USELIB is not set

CONFIG_LOG_BUF_SHIFT=14

CONFIG_CC_OPTIMIZE_FOR_SIZE=y

# CONFIG_AIO is not set

arch/x86/configs/i386_defconfig

+0 −1
Original line number Diff line number Diff line 
CONFIG_WERROR=y

CONFIG_SYSVIPC=y

CONFIG_POSIX_MQUEUE=y

CONFIG_USELIB=y

CONFIG_AUDIT=y

CONFIG_NO_HZ=y

CONFIG_HIGH_RES_TIMERS=y

arch/xtensa/configs/cadence_csp_defconfig

+0 −1
Original line number Diff line number Diff line 
CONFIG_SYSVIPC=y

CONFIG_POSIX_MQUEUE=y

CONFIG_USELIB=y

CONFIG_NO_HZ_IDLE=y

CONFIG_HIGH_RES_TIMERS=y

CONFIG_IRQ_TIME_ACCOUNTING=y

fs/binfmt_elf.c

+0 −76
Original line number Diff line number Diff line
@@ -68,12 +68,6 @@ 


static int load_elf_binary(struct linux_binprm *bprm);



#ifdef CONFIG_USELIB

static int load_elf_library(struct file *);

#else

#define load_elf_library NULL

#endif



/*

 * If we don't support core dumping, then supply a NULL so we

 * don't even try.
@@ -101,7 +95,6 @@ static int elf_core_dump(struct coredump_params *cprm); 
static struct linux_binfmt elf_format = {

	.module		= THIS_MODULE,

	.load_binary	= load_elf_binary,

	.load_shlib	= load_elf_library,

#ifdef CONFIG_COREDUMP

	.core_dump	= elf_core_dump,

	.min_coredump	= ELF_EXEC_PAGESIZE,
@@ -1361,75 +1354,6 @@ static int load_elf_binary(struct linux_binprm *bprm) 
	goto out;

}



#ifdef CONFIG_USELIB

/* This is really simpleminded and specialized - we are loading an

   a.out library that is given an ELF header. */

static int load_elf_library(struct file *file)

{

	struct elf_phdr *elf_phdata;

	struct elf_phdr *eppnt;

	int retval, error, i, j;

	struct elfhdr elf_ex;



	error = -ENOEXEC;

	retval = elf_read(file, &elf_ex, sizeof(elf_ex), 0);

	if (retval < 0)

		goto out;



	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)

		goto out;



	/* First of all, some simple consistency checks */

	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||

	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)

		goto out;

	if (elf_check_fdpic(&elf_ex))

		goto out;



	/* Now read in all of the header information */



	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;

	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */



	error = -ENOMEM;

	elf_phdata = kmalloc(j, GFP_KERNEL);

	if (!elf_phdata)

		goto out;



	eppnt = elf_phdata;

	error = -ENOEXEC;

	retval = elf_read(file, eppnt, j, elf_ex.e_phoff);

	if (retval < 0)

		goto out_free_ph;



	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)

		if ((eppnt + i)->p_type == PT_LOAD)

			j++;

	if (j != 1)

		goto out_free_ph;



	while (eppnt->p_type != PT_LOAD)

		eppnt++;



	/* Now use mmap to map the library into memory. */

	error = elf_load(file, ELF_PAGESTART(eppnt->p_vaddr),

			eppnt,

			PROT_READ | PROT_WRITE | PROT_EXEC,

			MAP_FIXED_NOREPLACE | MAP_PRIVATE,

			0);



	if (error != ELF_PAGESTART(eppnt->p_vaddr))

		goto out_free_ph;



	error = 0;



out_free_ph:

	kfree(elf_phdata);

out:

	return error;

}

#endif /* #ifdef CONFIG_USELIB */



#ifdef CONFIG_ELF_CORE

/*

 * ELF core dumper

fs/exec.c

+0 −60
Original line number Diff line number Diff line
@@ -115,66 +115,6 @@ bool path_noexec(const struct path *path) 
	       (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);

}



#ifdef CONFIG_USELIB

/*

 * Note that a shared library must be both readable and executable due to

 * security reasons.

 *

 * Also note that we take the address to load from the file itself.

 */

SYSCALL_DEFINE1(uselib, const char __user *, library)

{

	struct linux_binfmt *fmt;

	struct file *file;

	struct filename *tmp = getname(library);

	int error = PTR_ERR(tmp);

	static const struct open_flags uselib_flags = {

		.open_flag = O_LARGEFILE | O_RDONLY,

		.acc_mode = MAY_READ | MAY_EXEC,

		.intent = LOOKUP_OPEN,

		.lookup_flags = LOOKUP_FOLLOW,

	};



	if (IS_ERR(tmp))

		goto out;



	file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);

	putname(tmp);

	error = PTR_ERR(file);

	if (IS_ERR(file))

		goto out;



	/*

	 * Check do_open_execat() for an explanation.

	 */

	error = -EACCES;

	if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode)) ||

	    path_noexec(&file->f_path))

		goto exit;



	error = -ENOEXEC;



	read_lock(&binfmt_lock);

	list_for_each_entry(fmt, &formats, lh) {

		if (!fmt->load_shlib)

			continue;

		if (!try_module_get(fmt->module))

			continue;

		read_unlock(&binfmt_lock);

		error = fmt->load_shlib(file);

		read_lock(&binfmt_lock);

		put_binfmt(fmt);

		if (error != -ENOEXEC)

			break;

	}

	read_unlock(&binfmt_lock);

exit:

	fput(file);

out:

	return error;

}

#endif /* #ifdef CONFIG_USELIB */



#ifdef CONFIG_MMU

/*

 * The nascent bprm->mm is not visible until exec_mmap() but it can