| From c307459b9d1fcb8bbf3ea5a4162979532322ef77 Mon Sep 17 00:00:00 2001 |
| From: Kees Cook <keescook@chromium.org> |
| Date: Fri, 2 Oct 2020 10:38:13 -0700 |
| Subject: fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum |
| |
| From: Kees Cook <keescook@chromium.org> |
| |
| commit c307459b9d1fcb8bbf3ea5a4162979532322ef77 upstream. |
| |
| FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs |
| that are interested in filtering between types of things. The "how" |
| should be an internal detail made uninteresting to the LSMs. |
| |
| Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") |
| Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") |
| Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") |
| Signed-off-by: Kees Cook <keescook@chromium.org> |
| Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> |
| Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> |
| Acked-by: Scott Branden <scott.branden@broadcom.com> |
| Cc: stable@vger.kernel.org |
| Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/base/firmware_loader/main.c | 5 ++--- |
| fs/exec.c | 7 ++++--- |
| include/linux/fs.h | 1 - |
| kernel/module.c | 2 +- |
| security/integrity/digsig.c | 2 +- |
| security/integrity/ima/ima_fs.c | 2 +- |
| security/integrity/ima/ima_main.c | 6 ++---- |
| 7 files changed, 11 insertions(+), 14 deletions(-) |
| |
| --- a/drivers/base/firmware_loader/main.c |
| +++ b/drivers/base/firmware_loader/main.c |
| @@ -470,14 +470,12 @@ fw_get_filesystem_firmware(struct device |
| int i, len; |
| int rc = -ENOENT; |
| char *path; |
| - enum kernel_read_file_id id = READING_FIRMWARE; |
| size_t msize = INT_MAX; |
| void *buffer = NULL; |
| |
| /* Already populated data member means we're loading into a buffer */ |
| if (!decompress && fw_priv->data) { |
| buffer = fw_priv->data; |
| - id = READING_FIRMWARE_PREALLOC_BUFFER; |
| msize = fw_priv->allocated_size; |
| } |
| |
| @@ -501,7 +499,8 @@ fw_get_filesystem_firmware(struct device |
| |
| /* load firmware files from the mount namespace of init */ |
| rc = kernel_read_file_from_path_initns(path, &buffer, |
| - &size, msize, id); |
| + &size, msize, |
| + READING_FIRMWARE); |
| if (rc) { |
| if (rc != -ENOENT) |
| dev_warn(device, "loading %s failed with error %d\n", |
| --- a/fs/exec.c |
| +++ b/fs/exec.c |
| @@ -955,6 +955,7 @@ int kernel_read_file(struct file *file, |
| { |
| loff_t i_size, pos; |
| ssize_t bytes = 0; |
| + void *allocated = NULL; |
| int ret; |
| |
| if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) |
| @@ -978,8 +979,8 @@ int kernel_read_file(struct file *file, |
| goto out; |
| } |
| |
| - if (id != READING_FIRMWARE_PREALLOC_BUFFER) |
| - *buf = vmalloc(i_size); |
| + if (!*buf) |
| + *buf = allocated = vmalloc(i_size); |
| if (!*buf) { |
| ret = -ENOMEM; |
| goto out; |
| @@ -1008,7 +1009,7 @@ int kernel_read_file(struct file *file, |
| |
| out_free: |
| if (ret < 0) { |
| - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { |
| + if (allocated) { |
| vfree(*buf); |
| *buf = NULL; |
| } |
| --- a/include/linux/fs.h |
| +++ b/include/linux/fs.h |
| @@ -2861,7 +2861,6 @@ extern int do_pipe_flags(int *, int); |
| #define __kernel_read_file_id(id) \ |
| id(UNKNOWN, unknown) \ |
| id(FIRMWARE, firmware) \ |
| - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ |
| id(MODULE, kernel-module) \ |
| id(KEXEC_IMAGE, kexec-image) \ |
| id(KEXEC_INITRAMFS, kexec-initramfs) \ |
| --- a/kernel/module.c |
| +++ b/kernel/module.c |
| @@ -4028,7 +4028,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, c |
| { |
| struct load_info info = { }; |
| loff_t size; |
| - void *hdr; |
| + void *hdr = NULL; |
| int err; |
| |
| err = may_init_module(); |
| --- a/security/integrity/digsig.c |
| +++ b/security/integrity/digsig.c |
| @@ -169,7 +169,7 @@ int __init integrity_add_key(const unsig |
| |
| int __init integrity_load_x509(const unsigned int id, const char *path) |
| { |
| - void *data; |
| + void *data = NULL; |
| loff_t size; |
| int rc; |
| key_perm_t perm; |
| --- a/security/integrity/ima/ima_fs.c |
| +++ b/security/integrity/ima/ima_fs.c |
| @@ -272,7 +272,7 @@ static const struct file_operations ima_ |
| |
| static ssize_t ima_read_policy(char *path) |
| { |
| - void *data; |
| + void *data = NULL; |
| char *datap; |
| loff_t size; |
| int rc, pathlen = strlen(path); |
| --- a/security/integrity/ima/ima_main.c |
| +++ b/security/integrity/ima/ima_main.c |
| @@ -621,19 +621,17 @@ void ima_post_path_mknod(struct dentry * |
| int ima_read_file(struct file *file, enum kernel_read_file_id read_id) |
| { |
| /* |
| - * READING_FIRMWARE_PREALLOC_BUFFER |
| - * |
| * Do devices using pre-allocated memory run the risk of the |
| * firmware being accessible to the device prior to the completion |
| * of IMA's signature verification any more than when using two |
| - * buffers? |
| + * buffers? It may be desirable to include the buffer address |
| + * in this API and walk all the dma_map_single() mappings to check. |
| */ |
| return 0; |
| } |
| |
| const int read_idmap[READING_MAX_ID] = { |
| [READING_FIRMWARE] = FIRMWARE_CHECK, |
| - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, |
| [READING_MODULE] = MODULE_CHECK, |
| [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, |
| [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK, |