Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Intel Memory Protection Keys management
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * Copyright (c) 2015, Intel Corporation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <linux/debugfs.h>		/* debugfs_create_u32()		*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <linux/mm_types.h>             /* mm_struct, vma, etc...       */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/pkeys.h>                /* PKEY_*                       */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <uapi/asm-generic/mman-common.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <asm/cpufeature.h>             /* boot_cpu_has, ...            */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <asm/mmu_context.h>            /* vma_pkey()                   */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <asm/fpu/internal.h>		/* init_fpstate			*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) int __execute_only_pkey(struct mm_struct *mm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 	bool need_to_set_mm_pkey = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 	int execute_only_pkey = mm->context.execute_only_pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 	/* Do we need to assign a pkey for mm's execute-only maps? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	if (execute_only_pkey == -1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 		/* Go allocate one to use, which might fail */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 		execute_only_pkey = mm_pkey_alloc(mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 		if (execute_only_pkey < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 			return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 		need_to_set_mm_pkey = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	 * We do not want to go through the relatively costly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	 * dance to set PKRU if we do not need to.  Check it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	 * first and assume that if the execute-only pkey is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 	 * write-disabled that we do not have to set it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	 * ourselves.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	if (!need_to_set_mm_pkey &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	    !__pkru_allows_read(read_pkru(), execute_only_pkey)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 		return execute_only_pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	 * Set up PKRU so that it denies access for everything
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	 * other than execution.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	ret = arch_set_user_pkey_access(current, execute_only_pkey,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 			PKEY_DISABLE_ACCESS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	 * If the PKRU-set operation failed somehow, just return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	 * 0 and effectively disable execute-only support.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	if (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		mm_set_pkey_free(mm, execute_only_pkey);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	/* We got one, store it and use it from here on out */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	if (need_to_set_mm_pkey)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		mm->context.execute_only_pkey = execute_only_pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	return execute_only_pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	/* Do this check first since the vm_flags should be hot */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	if ((vma->vm_flags & VM_ACCESS_FLAGS) != VM_EXEC)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	if (vma_pkey(vma) != vma->vm_mm->context.execute_only_pkey)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  * This is only called for *plain* mprotect calls.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	 * Is this an mprotect_pkey() call?  If so, never
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	 * override the value that came from the user.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	if (pkey != -1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		return pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	 * The mapping is execute-only.  Go try to get the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	 * execute-only protection key.  If we fail to do that,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	 * fall through as if we do not have execute-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	 * support in this mm.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	if (prot == PROT_EXEC) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		pkey = execute_only_pkey(vma->vm_mm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		if (pkey > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 			return pkey;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	} else if (vma_is_pkey_exec_only(vma)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 		 * Protections are *not* PROT_EXEC, but the mapping
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 		 * is using the exec-only pkey.  This mapping was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		 * PROT_EXEC and will no longer be.  Move back to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 		 * the default pkey.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		return ARCH_DEFAULT_PKEY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	 * This is a vanilla, non-pkey mprotect (or we failed to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	 * setup execute-only), inherit the pkey from the VMA we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	 * are working on.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	return vma_pkey(vma);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) #define PKRU_AD_KEY(pkey)	(PKRU_AD_BIT << ((pkey) * PKRU_BITS_PER_PKEY))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)  * Make the default PKRU value (at execve() time) as restrictive
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)  * as possible.  This ensures that any threads clone()'d early
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)  * in the process's lifetime will not accidentally get access
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)  * to data which is pkey-protected later on.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 		      PKRU_AD_KEY( 4) | PKRU_AD_KEY( 5) | PKRU_AD_KEY( 6) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		      PKRU_AD_KEY( 7) | PKRU_AD_KEY( 8) | PKRU_AD_KEY( 9) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		      PKRU_AD_KEY(10) | PKRU_AD_KEY(11) | PKRU_AD_KEY(12) |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		      PKRU_AD_KEY(13) | PKRU_AD_KEY(14) | PKRU_AD_KEY(15);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  * Called from the FPU code when creating a fresh set of FPU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  * registers.  This is called from a very specific context where
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  * we know the FPU regstiers are safe for use and we can use PKRU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  * directly.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) void copy_init_pkru_to_fpregs(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	u32 init_pkru_value_snapshot = READ_ONCE(init_pkru_value);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	 * Override the PKRU state that came from 'init_fpstate'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	 * with the baseline from the process.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 	write_pkru(init_pkru_value_snapshot);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) static ssize_t init_pkru_read_file(struct file *file, char __user *user_buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			     size_t count, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 	char buf[32];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	unsigned int len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	len = sprintf(buf, "0x%x\n", init_pkru_value);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) static ssize_t init_pkru_write_file(struct file *file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		 const char __user *user_buf, size_t count, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	struct pkru_state *pk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	char buf[32];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	ssize_t len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	u32 new_init_pkru;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	len = min(count, sizeof(buf) - 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	if (copy_from_user(buf, user_buf, len))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	/* Make the buffer a valid string that we can not overrun */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	buf[len] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	if (kstrtouint(buf, 0, &new_init_pkru))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	 * Don't allow insane settings that will blow the system
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	 * up immediately if someone attempts to disable access
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	 * or writes to pkey 0.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	if (new_init_pkru & (PKRU_AD_BIT|PKRU_WD_BIT))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	WRITE_ONCE(init_pkru_value, new_init_pkru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	pk = get_xsave_addr(&init_fpstate.xsave, XFEATURE_PKRU);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	if (!pk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 	pk->pkru = new_init_pkru;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 	return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) static const struct file_operations fops_init_pkru = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	.read = init_pkru_read_file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	.write = init_pkru_write_file,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	.llseek = default_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) static int __init create_init_pkru_value(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	debugfs_create_file("init_pkru", S_IRUSR | S_IWUSR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			arch_debugfs_dir, NULL, &fops_init_pkru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) late_initcall(create_init_pkru_value);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) static __init int setup_init_pkru(char *opt)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	u32 new_init_pkru;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	if (kstrtouint(opt, 0, &new_init_pkru))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	WRITE_ONCE(init_pkru_value, new_init_pkru);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) __setup("init_pkru=", setup_init_pkru);