[PATCH v3 04/19] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
From: Kees Cook <hidden>
Date: 2020-07-24 21:38:41
Also in:
linux-efi, linux-integrity, linux-kselftest, lkml, selinux, stable
Subsystem:
driver core, kobjects, debugfs and sysfs, exec & binfmt api, elf, extended verification module (evm), filesystems (vfs and infrastructure), firmware loader (request_firmware), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Kees Cook, Mimi Zohar, Roberto Sassu, Alexander Viro, Christian Brauner, Luis Chamberlain, Russ Weight, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
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)")
Cc: stable@vger.kernel.org
Acked-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Kees Cook <redacted>
---
To aid in backporting, this change is made before moving
kernel_read_file() to separate header/source files.
---
drivers/base/firmware_loader/main.c | 5 ++---
fs/exec.c | 7 ++++---
include/linux/fs.h | 2 +-
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, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index ca871b13524e..c2f57cedcd6f 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c@@ -465,14 +465,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, 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; }
@@ -496,7 +494,8 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, /* 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",
diff --git a/fs/exec.c b/fs/exec.c
index e6e8a9a70327..2bf549757ce7 100644
--- a/fs/exec.c
+++ b/fs/exec.c@@ -927,6 +927,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, { 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)
@@ -950,8 +951,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, 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;
@@ -980,7 +981,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, out_free: if (ret < 0) { - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { + if (allocated) { vfree(*buf); *buf = NULL; }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3f881a892ea7..95fc775ed937 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -2993,10 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode) #endif extern int do_pipe_flags(int *, int); +/* This is a list of *what* is being read, not *how*. */ #define __kernel_read_file_id(id) \ id(UNKNOWN, unknown) \ id(FIRMWARE, firmware) \ - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ id(FIRMWARE_EFI_EMBEDDED, firmware) \ id(MODULE, kernel-module) \ id(KEXEC_IMAGE, kexec-image) \
diff --git a/kernel/module.c b/kernel/module.c
index 0c6573b98c36..26105148f4d2 100644
--- a/kernel/module.c
+++ b/kernel/module.c@@ -3988,7 +3988,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { struct load_info info = { }; loff_t size; - void *hdr; + void *hdr = NULL; int err; err = may_init_module();
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index e9cbadade74b..ac02b7632353 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c@@ -169,7 +169,7 @@ int __init integrity_add_key(const unsigned int id, const void *data, 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;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index e3fcad871861..15a44c5022f7 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c@@ -272,7 +272,7 @@ static const struct file_operations ima_ascii_measurements_ops = { static ssize_t ima_read_policy(char *path) { - void *data; + void *data = NULL; char *datap; loff_t size; int rc, pathlen = strlen(path);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c1583d98c5e5..f80ee4ce4669 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c@@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *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,
--
2.25.1