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fs/kernel_read_file: Remove redundant size argument
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In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
code, with callers adjusted. (VFS reads already cannot be larger than
INT_MAX.)

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: James Morris <[email protected]>
Acked-by: Scott Branden <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@kees @gregkh
kees authored and gregkh committed Oct 5, 2020
1 parent 5287b07 commit f7a4f68
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Showing 7 changed files with 36 additions and 34 deletions.
10 changes: 6 additions & 4 deletions drivers/base/firmware_loader/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -467,7 +467,7 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
size_t in_size,
const void *in_buffer))
{
loff_t size;
size_t size;
int i, len;
int rc = -ENOENT;
char *path;
Expand Down Expand Up @@ -499,10 +499,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
fw_priv->size = 0;

/* load firmware files from the mount namespace of init */
rc = kernel_read_file_from_path_initns(path, &buffer,
&size, msize,
rc = kernel_read_file_from_path_initns(path, &buffer, msize,
READING_FIRMWARE);
if (rc) {
if (rc < 0) {
if (rc != -ENOENT)
dev_warn(device, "loading %s failed with error %d\n",
path, rc);
Expand All @@ -511,6 +510,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
path);
continue;
}
size = rc;
rc = 0;

dev_dbg(device, "Loading firmware from %s\n", path);
if (decompress) {
dev_dbg(device, "f/w decompressing %s\n",
Expand Down
20 changes: 9 additions & 11 deletions fs/kernel_read_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
#include <linux/security.h>
#include <linux/vmalloc.h>

int kernel_read_file(struct file *file, void **buf, loff_t *size,
int kernel_read_file(struct file *file, void **buf,
loff_t max_size, enum kernel_read_file_id id)
{
loff_t i_size, pos;
Expand All @@ -29,7 +29,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
ret = -EINVAL;
goto out;
}
if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
if (i_size > INT_MAX || (max_size > 0 && i_size > max_size)) {
ret = -EFBIG;
goto out;
}
Expand Down Expand Up @@ -59,8 +59,6 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
}

ret = security_kernel_post_read_file(file, *buf, i_size, id);
if (!ret)
*size = pos;

out_free:
if (ret < 0) {
Expand All @@ -72,11 +70,11 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,

out:
allow_write_access(file);
return ret;
return ret == 0 ? pos : ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file);

int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
int kernel_read_file_from_path(const char *path, void **buf,
loff_t max_size, enum kernel_read_file_id id)
{
struct file *file;
Expand All @@ -89,14 +87,14 @@ int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
if (IS_ERR(file))
return PTR_ERR(file);

ret = kernel_read_file(file, buf, size, max_size, id);
ret = kernel_read_file(file, buf, max_size, id);
fput(file);
return ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file_from_path);

int kernel_read_file_from_path_initns(const char *path, void **buf,
loff_t *size, loff_t max_size,
loff_t max_size,
enum kernel_read_file_id id)
{
struct file *file;
Expand All @@ -115,13 +113,13 @@ int kernel_read_file_from_path_initns(const char *path, void **buf,
if (IS_ERR(file))
return PTR_ERR(file);

ret = kernel_read_file(file, buf, size, max_size, id);
ret = kernel_read_file(file, buf, max_size, id);
fput(file);
return ret;
}
EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);

int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
int kernel_read_file_from_fd(int fd, void **buf, loff_t max_size,
enum kernel_read_file_id id)
{
struct fd f = fdget(fd);
Expand All @@ -130,7 +128,7 @@ int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
if (!f.file)
goto out;

ret = kernel_read_file(f.file, buf, size, max_size, id);
ret = kernel_read_file(f.file, buf, max_size, id);
out:
fdput(f);
return ret;
Expand Down
8 changes: 4 additions & 4 deletions include/linux/kernel_read_file.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,16 +36,16 @@ static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
}

int kernel_read_file(struct file *file,
void **buf, loff_t *size, loff_t max_size,
void **buf, loff_t max_size,
enum kernel_read_file_id id);
int kernel_read_file_from_path(const char *path,
void **buf, loff_t *size, loff_t max_size,
void **buf, loff_t max_size,
enum kernel_read_file_id id);
int kernel_read_file_from_path_initns(const char *path,
void **buf, loff_t *size, loff_t max_size,
void **buf, loff_t max_size,
enum kernel_read_file_id id);
int kernel_read_file_from_fd(int fd,
void **buf, loff_t *size, loff_t max_size,
void **buf, loff_t max_size,
enum kernel_read_file_id id);

#endif /* _LINUX_KERNEL_READ_FILE_H */
14 changes: 7 additions & 7 deletions kernel/kexec_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -220,13 +220,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
{
int ret;
void *ldata;
loff_t size;

ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
&size, INT_MAX, READING_KEXEC_IMAGE);
if (ret)
INT_MAX, READING_KEXEC_IMAGE);
if (ret < 0)
return ret;
image->kernel_buf_len = size;
image->kernel_buf_len = ret;

/* Call arch image probe handlers */
ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
Expand All @@ -243,11 +242,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
/* It is possible that there no initramfs is being loaded */
if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
&size, INT_MAX,
INT_MAX,
READING_KEXEC_INITRAMFS);
if (ret)
if (ret < 0)
goto out;
image->initrd_buf_len = size;
image->initrd_buf_len = ret;
ret = 0;
}

if (cmdline_len) {
Expand Down
7 changes: 3 additions & 4 deletions kernel/module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4035,7 +4035,6 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
{
struct load_info info = { };
loff_t size;
void *hdr = NULL;
int err;

Expand All @@ -4049,12 +4048,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
|MODULE_INIT_IGNORE_VERMAGIC))
return -EINVAL;

err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX,
err = kernel_read_file_from_fd(fd, &hdr, INT_MAX,
READING_MODULE);
if (err)
if (err < 0)
return err;
info.hdr = hdr;
info.len = size;
info.len = err;

return load_module(&info, uargs, flags);
}
Expand Down
5 changes: 3 additions & 2 deletions security/integrity/digsig.c
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Original file line number Diff line number Diff line change
Expand Up @@ -171,16 +171,17 @@ 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 = NULL;
loff_t size;
size_t size;
int rc;
key_perm_t perm;

rc = kernel_read_file_from_path(path, &data, &size, 0,
rc = kernel_read_file_from_path(path, &data, 0,
READING_X509_CERTIFICATE);
if (rc < 0) {
pr_err("Unable to open file: %s (%d)", path, rc);
return rc;
}
size = rc;

perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;

Expand Down
6 changes: 4 additions & 2 deletions security/integrity/ima/ima_fs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -275,7 +275,7 @@ static ssize_t ima_read_policy(char *path)
{
void *data = NULL;
char *datap;
loff_t size;
size_t size;
int rc, pathlen = strlen(path);

char *p;
Expand All @@ -284,11 +284,13 @@ static ssize_t ima_read_policy(char *path)
datap = path;
strsep(&datap, "\n");

rc = kernel_read_file_from_path(path, &data, &size, 0, READING_POLICY);
rc = kernel_read_file_from_path(path, &data, 0, READING_POLICY);
if (rc < 0) {
pr_err("Unable to open file: %s (%d)", path, rc);
return rc;
}
size = rc;
rc = 0;

datap = data;
while (size > 0 && (p = strsep(&datap, "\n"))) {
Expand Down

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