Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx> wrote:
> Thanks, David. I've also compiled and done some basic boot testing. I did
> need to add #include <linux/binfmts.h> to fs/coda/dir.c (this again may have
> been in one of your follow-on emails, but I didn't notice it).
Good point. Hmmm... I wonder if I should move kernel_read() to be next to
vfs_read() in fs/read_write.c and make a new function read_exec() to take a
bprm and call kernel_read() with the cred override applied. See the attached
patch.
This way non-binfmt stuff isn't calling into exec code.
Also, kernel_read() and read_exec() really ought to take a size_t count and
return an ssize_t value, though it isn't really a problem via count isn't too
big.
David
---
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index a8dddd2..6deedd3 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -445,7 +445,7 @@ static int load_aout_library(struct file *file)
inode = file->f_path.dentry->d_inode;
retval = -ENOEXEC;
- error = kernel_read(NULL, file, 0, &ex, sizeof(ex));
+ error = kernel_read(file, 0, &ex, sizeof(ex));
if (error != sizeof(ex))
goto out;
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index 8890161..aef4f91 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -379,7 +379,7 @@ static int load_aout_library(struct file *file)
inode = file->f_path.dentry->d_inode;
retval = -ENOEXEC;
- error = kernel_read(NULL, file, 0, &ex, sizeof(ex));
+ error = kernel_read(file, 0, &ex, sizeof(ex));
if (error != sizeof(ex))
goto out;
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 9f08098..5f19711 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -416,7 +416,7 @@ static unsigned long load_elf_interp(struct linux_binprm *bprm,
if (!elf_phdata)
goto out;
- retval = kernel_read(NULL, interpreter, interp_elf_ex->e_phoff,
+ retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
elf_phdata, size);
error = -EIO;
if (retval != size) {
@@ -612,8 +612,8 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
if (!elf_phdata)
goto out;
- retval = kernel_read(bprm, bprm->file, loc->elf_ex.e_phoff,
- elf_phdata, size);
+ retval = read_exec(bprm, bprm->file, loc->elf_ex.e_phoff,
+ elf_phdata, size);
if (retval != size) {
if (retval >= 0)
retval = -EIO;
@@ -646,10 +646,10 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
if (!elf_interpreter)
goto out_free_ph;
- retval = kernel_read(bprm, bprm->file,
- elf_ppnt->p_offset,
- elf_interpreter,
- elf_ppnt->p_filesz);
+ retval = read_exec(bprm, bprm->file,
+ elf_ppnt->p_offset,
+ elf_interpreter,
+ elf_ppnt->p_filesz);
if (retval != elf_ppnt->p_filesz) {
if (retval >= 0)
retval = -EIO;
@@ -1007,7 +1007,7 @@ static int load_elf_library(struct file *file)
struct elfhdr elf_ex;
error = -ENOEXEC;
- retval = kernel_read(NULL, file, 0, &elf_ex, sizeof(elf_ex));
+ retval = kernel_read(file, 0, &elf_ex, sizeof(elf_ex));
if (retval != sizeof(elf_ex))
goto out;
@@ -1031,7 +1031,7 @@ static int load_elf_library(struct file *file)
eppnt = elf_phdata;
error = -ENOEXEC;
- retval = kernel_read(NULL, file, elf_ex.e_phoff, eppnt, j);
+ retval = kernel_read(file, elf_ex.e_phoff, eppnt, j);
if (retval != j)
goto out_free_ph;
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index a8e07b9..fb7bab1 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -138,8 +138,8 @@ static int elf_fdpic_fetch_phdrs(struct linux_binprm *bprm,
if (!params->phdrs)
return -ENOMEM;
- retval = kernel_read(bprm, file, params->hdr.e_phoff,
- (char *) params->phdrs, size);
+ retval = read_exec(bprm, file, params->hdr.e_phoff,
+ params->phdrs, size);
if (unlikely(retval != size))
return retval < 0 ? retval : -ENOEXEC;
@@ -218,10 +218,10 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm,
if (!interpreter_name)
goto error;
- retval = kernel_read(bprm, bprm->file,
- phdr->p_offset,
- interpreter_name,
- phdr->p_filesz);
+ retval = read_exec(bprm, bprm->file,
+ phdr->p_offset,
+ interpreter_name,
+ phdr->p_filesz);
if (unlikely(retval != phdr->p_filesz)) {
if (retval >= 0)
retval = -ENOEXEC;
diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
index e27f6ad..7663575 100644
--- a/fs/binfmt_som.c
+++ b/fs/binfmt_som.c
@@ -211,8 +211,8 @@ load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
if (!hpuxhdr)
goto out;
- retval = kernel_read(bprm, bprm->file, som_ex->aux_header_location,
- hpuxhdr, size);
+ retval = read_exec(bprm, bprm->file, som_ex->aux_header_location,
+ hpuxhdr, size);
if (retval != size) {
if (retval >= 0)
retval = -EIO;
diff --git a/fs/coda/dir.c b/fs/coda/dir.c
index e0c7f4a..b363d77 100644
--- a/fs/coda/dir.c
+++ b/fs/coda/dir.c
@@ -482,7 +482,7 @@ static int coda_venus_readdir(struct file *coda_file, void *buf,
}
while (1) {
/* read entries from the directory file */
- ret = kernel_read(NULL, host_file, coda_file->f_pos - 2, vdir,
+ ret = kernel_read(host_file, coda_file->f_pos - 2, vdir,
sizeof(*vdir));
if (ret < 0) {
printk(KERN_ERR "coda readdir: read dir %s failed %d\n",
diff --git a/fs/exec.c b/fs/exec.c
index c40a126..7b66a5d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -779,7 +779,7 @@ exit:
EXPORT_SYMBOL(open_exec);
/**
- * kernel_read - Read data from an executable
+ * read_exec - Read data from an executable
* @bprm: Execution state (or NULL if after the point of no return)
* @file: File to read from
* @offset: File offset to read from
@@ -788,29 +788,20 @@ EXPORT_SYMBOL(open_exec);
*
* Read some data from an executable
*/
-int kernel_read(struct linux_binprm *bprm,
- struct file *file, loff_t offset,
- void *addr, unsigned long count)
+ssize_t read_exec(struct linux_binprm *bprm,
+ struct file *file, loff_t offset, void *addr, size_t count)
{
const struct cred *saved_cred = NULL;
- mm_segment_t old_fs;
- loff_t pos = offset;
- int result;
+ ssize_t result;
- if (bprm && bprm->cred)
+ if (bprm->cred)
saved_cred = override_creds(bprm->cred);
-
- old_fs = get_fs();
- set_fs(get_ds());
- /* The cast to a user pointer is valid due to the set_fs() */
- result = vfs_read(file, (void __user *)addr, count, &pos);
- set_fs(old_fs);
-
+ result = kernel_read(file, offset, addr, count);
if (saved_cred)
revert_creds(saved_cred);
return result;
}
-EXPORT_SYMBOL(kernel_read);
+EXPORT_SYMBOL(read_exec);
static int exec_mmap(struct mm_struct *mm)
{
diff --git a/fs/read_write.c b/fs/read_write.c
index 5520f8a..875dbfc 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -333,6 +333,27 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
EXPORT_SYMBOL(vfs_read);
+/**
+ * kernel_read - Read data to a kernel buffer
+ * @file: File to read from
+ * @offset: File offset to read from
+ * @addr: The buffer to read into
+ * @count: The amount of data to read
+ */
+ssize_t kernel_read(struct file *file, loff_t offset, void *addr, size_t count)
+{
+ mm_segment_t old_fs = get_fs();
+ loff_t pos = offset;
+ ssize_t result;
+
+ set_fs(get_ds());
+ /* The cast to a user pointer is valid due to the set_fs() */
+ result = vfs_read(file, (void __user *)addr, count, &pos);
+ set_fs(old_fs);
+ return result;
+}
+EXPORT_SYMBOL(kernel_read);
+
ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 57ea660..b394f85 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -135,8 +135,8 @@ extern int copy_strings_kernel(int argc, const char *const *argv,
extern int prepare_bprm_creds(struct linux_binprm *bprm);
extern struct file *open_exec(const char *filename, struct linux_binprm *bprm);
extern void install_exec_creds(struct linux_binprm *bprm);
-extern int kernel_read(struct linux_binprm *, struct file *,
- loff_t, void *, unsigned long);
+extern ssize_t read_exec(struct linux_binprm *, struct file *,
+ loff_t, void *, unsigned long);
extern void install_exec_creds(struct linux_binprm *bprmw);
extern void do_coredump(long signr, int exit_code, struct pt_regs *regs);
extern void set_binfmt(struct linux_binfmt *new);
@@ -144,7 +144,7 @@ extern void free_bprm(struct linux_binprm *);
static inline int exec_read_header(struct linux_binprm *bprm, struct file *file)
{
- return kernel_read(bprm, file, 0, bprm->buf, BINPRM_BUF_SIZE);
+ return read_exec(bprm, file, 0, bprm->buf, BINPRM_BUF_SIZE);
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e1a44a9..42a1be2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1610,6 +1610,7 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
unsigned long, loff_t *);
extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
unsigned long, loff_t *);
+extern ssize_t kernel_read(struct file *, loff_t, void *, size_t);
struct super_operations {
struct inode *(*alloc_inode)(struct super_block *sb);
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 6877035..aa5672b 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -277,7 +277,7 @@ static int p9_fd_read(struct p9_client *client, void *v, int len)
if (!(ts->rd->f_flags & O_NONBLOCK))
P9_DPRINTK(P9_DEBUG_ERROR, "blocking read ...\n");
- ret = kernel_read(NULL, ts->rd, ts->rd->f_pos, v, len);
+ ret = kernel_read(ts->rd, ts->rd->f_pos, v, len);
if (ret <= 0 && ret != -ERESTARTSYS && ret != -EAGAIN)
client->status = Disconnected;
return ret;
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 0c93027..9b3ade7 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -63,7 +63,7 @@ int ima_calc_hash(struct file *file, char *digest)
while (offset < i_size) {
int rbuf_len;
- rbuf_len = kernel_read(NULL, file, offset, rbuf, PAGE_SIZE);
+ rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
if (rbuf_len < 0) {
rc = rbuf_len;
break;
--
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