diff options
| -rw-r--r-- | kernel/power/Kconfig | 12 | ||||
| -rw-r--r-- | kernel/power/swsusp.c | 164 |
2 files changed, 171 insertions, 5 deletions
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 2c7121d9bff1..917066a5767c 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -72,6 +72,18 @@ config PM_STD_PARTITION suspended image to. It will simply pick the first available swap device. +config SWSUSP_ENCRYPT + bool "Encrypt suspend image" + depends on SOFTWARE_SUSPEND && CRYPTO=y && (CRYPTO_AES=y || CRYPTO_AES_586=y || CRYPTO_AES_X86_64=y) + default "" + ---help--- + To prevent data gathering from swap after resume you can encrypt + the suspend image with a temporary key that is deleted on + resume. + + Note that the temporary key is stored unencrypted on disk while the + system is suspended. + config SUSPEND_SMP bool depends on HOTPLUG_CPU && X86 && PM diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c index 975b1648a806..b041cea2e878 100644 --- a/kernel/power/swsusp.c +++ b/kernel/power/swsusp.c @@ -31,6 +31,9 @@ * Alex Badea <vampire@go.ro>: * Fixed runaway init * + * Andreas Steinmetz <ast@domdv.de>: + * Added encrypted suspend option + * * More state savers are welcome. Especially for the scsi layer... * * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt @@ -71,8 +74,16 @@ #include <asm/tlbflush.h> #include <asm/io.h> +#include <linux/random.h> +#include <linux/crypto.h> +#include <asm/scatterlist.h> + #include "power.h" +#define CIPHER "aes" +#define MAXKEY 32 +#define MAXIV 32 + /* References to section boundaries */ extern const void __nosave_begin, __nosave_end; @@ -103,7 +114,8 @@ static suspend_pagedir_t *pagedir_save; #define SWSUSP_SIG "S1SUSPEND" static struct swsusp_header { - char reserved[PAGE_SIZE - 20 - sizeof(swp_entry_t)]; + char reserved[PAGE_SIZE - 20 - MAXKEY - MAXIV - sizeof(swp_entry_t)]; + u8 key_iv[MAXKEY+MAXIV]; swp_entry_t swsusp_info; char orig_sig[10]; char sig[10]; @@ -129,6 +141,131 @@ static struct swsusp_info swsusp_info; static unsigned short swapfile_used[MAX_SWAPFILES]; static unsigned short root_swap; +static int write_page(unsigned long addr, swp_entry_t * loc); +static int bio_read_page(pgoff_t page_off, void * page); + +static u8 key_iv[MAXKEY+MAXIV]; + +#ifdef CONFIG_SWSUSP_ENCRYPT + +static int crypto_init(int mode, void **mem) +{ + int error = 0; + int len; + char *modemsg; + struct crypto_tfm *tfm; + + modemsg = mode ? "suspend not possible" : "resume not possible"; + + tfm = crypto_alloc_tfm(CIPHER, CRYPTO_TFM_MODE_CBC); + if(!tfm) { + printk(KERN_ERR "swsusp: no tfm, %s\n", modemsg); + error = -EINVAL; + goto out; + } + + if(MAXKEY < crypto_tfm_alg_min_keysize(tfm)) { + printk(KERN_ERR "swsusp: key buffer too small, %s\n", modemsg); + error = -ENOKEY; + goto fail; + } + + if (mode) + get_random_bytes(key_iv, MAXKEY+MAXIV); + + len = crypto_tfm_alg_max_keysize(tfm); + if (len > MAXKEY) + len = MAXKEY; + + if (crypto_cipher_setkey(tfm, key_iv, len)) { + printk(KERN_ERR "swsusp: key setup failure, %s\n", modemsg); + error = -EKEYREJECTED; + goto fail; + } + + len = crypto_tfm_alg_ivsize(tfm); + + if (MAXIV < len) { + printk(KERN_ERR "swsusp: iv buffer too small, %s\n", modemsg); + error = -EOVERFLOW; + goto fail; + } + + crypto_cipher_set_iv(tfm, key_iv+MAXKEY, len); + + *mem=(void *)tfm; + + goto out; + +fail: crypto_free_tfm(tfm); +out: return error; +} + +static __inline__ void crypto_exit(void *mem) +{ + crypto_free_tfm((struct crypto_tfm *)mem); +} + +static __inline__ int crypto_write(struct pbe *p, void *mem) +{ + int error = 0; + struct scatterlist src, dst; + + src.page = virt_to_page(p->address); + src.offset = 0; + src.length = PAGE_SIZE; + dst.page = virt_to_page((void *)&swsusp_header); + dst.offset = 0; + dst.length = PAGE_SIZE; + + error = crypto_cipher_encrypt((struct crypto_tfm *)mem, &dst, &src, + PAGE_SIZE); + + if (!error) + error = write_page((unsigned long)&swsusp_header, + &(p->swap_address)); + return error; +} + +static __inline__ int crypto_read(struct pbe *p, void *mem) +{ + int error = 0; + struct scatterlist src, dst; + + error = bio_read_page(swp_offset(p->swap_address), (void *)p->address); + if (!error) { + src.offset = 0; + src.length = PAGE_SIZE; + dst.offset = 0; + dst.length = PAGE_SIZE; + src.page = dst.page = virt_to_page((void *)p->address); + + error = crypto_cipher_decrypt((struct crypto_tfm *)mem, &dst, + &src, PAGE_SIZE); + } + return error; +} +#else +static __inline__ int crypto_init(int mode, void *mem) +{ + return 0; +} + +static __inline__ void crypto_exit(void *mem) +{ +} + +static __inline__ int crypto_write(struct pbe *p, void *mem) +{ + return write_page(p->address, &(p->swap_address)); +} + +static __inline__ int crypto_read(struct pbe *p, void *mem) +{ + return bio_read_page(swp_offset(p->swap_address), (void *)p->address); +} +#endif + static int mark_swapfiles(swp_entry_t prev) { int error; @@ -140,6 +277,7 @@ static int mark_swapfiles(swp_entry_t prev) !memcmp("SWAPSPACE2",swsusp_header.sig, 10)) { memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10); memcpy(swsusp_header.sig,SWSUSP_SIG, 10); + memcpy(swsusp_header.key_iv, key_iv, MAXKEY+MAXIV); swsusp_header.swsusp_info = prev; error = rw_swap_page_sync(WRITE, swp_entry(root_swap, 0), @@ -286,6 +424,10 @@ static int data_write(void) int error = 0, i = 0; unsigned int mod = nr_copy_pages / 100; struct pbe *p; + void *tfm; + + if ((error = crypto_init(1, &tfm))) + return error; if (!mod) mod = 1; @@ -294,11 +436,14 @@ static int data_write(void) for_each_pbe (p, pagedir_nosave) { if (!(i%mod)) printk( "\b\b\b\b%3d%%", i / mod ); - if ((error = write_page(p->address, &(p->swap_address)))) + if ((error = crypto_write(p, tfm))) { + crypto_exit(tfm); return error; + } i++; } printk("\b\b\b\bdone\n"); + crypto_exit(tfm); return error; } @@ -400,6 +545,7 @@ static int write_suspend_image(void) if ((error = close_swap())) goto FreePagedir; Done: + memset(key_iv, 0, MAXKEY+MAXIV); return error; FreePagedir: free_pagedir_entries(); @@ -1212,6 +1358,8 @@ static int check_sig(void) return error; if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) { memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10); + memcpy(key_iv, swsusp_header.key_iv, MAXKEY+MAXIV); + memset(swsusp_header.key_iv, 0, MAXKEY+MAXIV); /* * Reset swap signature now. @@ -1239,6 +1387,10 @@ static int data_read(struct pbe *pblist) int error = 0; int i = 0; int mod = swsusp_info.image_pages / 100; + void *tfm; + + if ((error = crypto_init(0, &tfm))) + return error; if (!mod) mod = 1; @@ -1250,14 +1402,15 @@ static int data_read(struct pbe *pblist) if (!(i % mod)) printk("\b\b\b\b%3d%%", i / mod); - error = bio_read_page(swp_offset(p->swap_address), - (void *)p->address); - if (error) + if ((error = crypto_read(p, tfm))) { + crypto_exit(tfm); return error; + } i++; } printk("\b\b\b\bdone\n"); + crypto_exit(tfm); return error; } @@ -1385,6 +1538,7 @@ int swsusp_read(void) error = read_suspend_image(); blkdev_put(resume_bdev); + memset(key_iv, 0, MAXKEY+MAXIV); if (!error) pr_debug("swsusp: Reading resume file was successful\n"); |