diff options
Diffstat (limited to 'fs/debugfs/file.c')
| -rw-r--r-- | fs/debugfs/file.c | 141 |
1 files changed, 72 insertions, 69 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 93e4ca6b2ad7..634b09d18b77 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -19,6 +19,7 @@ #include <linux/atomic.h> #include <linux/device.h> #include <linux/poll.h> +#include <linux/security.h> #include "internal.h" @@ -136,6 +137,28 @@ void debugfs_file_put(struct dentry *dentry) } EXPORT_SYMBOL_GPL(debugfs_file_put); +/* + * Only permit access to world-readable files when the kernel is locked down. + * We also need to exclude any file that has ways to write or alter it as root + * can bypass the permissions check. + */ +static int debugfs_locked_down(struct inode *inode, + struct file *filp, + const struct file_operations *real_fops) +{ + if ((inode->i_mode & 07777) == 0444 && + !(filp->f_mode & FMODE_WRITE) && + !real_fops->unlocked_ioctl && + !real_fops->compat_ioctl && + !real_fops->mmap) + return 0; + + if (security_locked_down(LOCKDOWN_DEBUGFS)) + return -EPERM; + + return 0; +} + static int open_proxy_open(struct inode *inode, struct file *filp) { struct dentry *dentry = F_DENTRY(filp); @@ -147,6 +170,11 @@ static int open_proxy_open(struct inode *inode, struct file *filp) return r == -EIO ? -ENOENT : r; real_fops = debugfs_real_fops(filp); + + r = debugfs_locked_down(inode, filp, real_fops); + if (r) + goto out; + real_fops = fops_get(real_fops); if (!real_fops) { /* Huh? Module did not clean up after itself at exit? */ @@ -272,6 +300,11 @@ static int full_proxy_open(struct inode *inode, struct file *filp) return r == -EIO ? -ENOENT : r; real_fops = debugfs_real_fops(filp); + + r = debugfs_locked_down(inode, filp, real_fops); + if (r) + goto out; + real_fops = fops_get(real_fops); if (!real_fops) { /* Huh? Module did not cleanup after itself at exit? */ @@ -390,20 +423,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n"); * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the debugfs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be - * returned. - * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will - * be returned. */ -struct dentry *debugfs_create_u8(const char *name, umode_t mode, - struct dentry *parent, u8 *value) +void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent, + u8 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8, &fops_u8_ro, &fops_u8_wo); } EXPORT_SYMBOL_GPL(debugfs_create_u8); @@ -435,20 +459,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n"); * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the debugfs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be - * returned. - * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will - * be returned. */ -struct dentry *debugfs_create_u16(const char *name, umode_t mode, - struct dentry *parent, u16 *value) +void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent, + u16 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16, &fops_u16_ro, &fops_u16_wo); } EXPORT_SYMBOL_GPL(debugfs_create_u16); @@ -484,10 +499,10 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n"); * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_u32(const char *name, umode_t mode, @@ -526,20 +541,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n"); * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so * set, it can be read from, and written to. - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the debugfs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be - * returned. - * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will - * be returned. */ -struct dentry *debugfs_create_u64(const char *name, umode_t mode, - struct dentry *parent, u64 *value) +void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent, + u64 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64, &fops_u64_ro, &fops_u64_wo); } EXPORT_SYMBOL_GPL(debugfs_create_u64); @@ -578,10 +584,10 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n"); * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_ulong(const char *name, umode_t mode, @@ -630,10 +636,10 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n"); * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_x8(const char *name, umode_t mode, - struct dentry *parent, u8 *value) +void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent, + u8 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8, &fops_x8_ro, &fops_x8_wo); } EXPORT_SYMBOL_GPL(debugfs_create_x8); @@ -648,10 +654,10 @@ EXPORT_SYMBOL_GPL(debugfs_create_x8); * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_x16(const char *name, umode_t mode, - struct dentry *parent, u16 *value) +void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent, + u16 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16, &fops_x16_ro, &fops_x16_wo); } EXPORT_SYMBOL_GPL(debugfs_create_x16); @@ -666,10 +672,10 @@ EXPORT_SYMBOL_GPL(debugfs_create_x16); * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_x32(const char *name, umode_t mode, - struct dentry *parent, u32 *value) +void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent, + u32 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32, &fops_x32_ro, &fops_x32_wo); } EXPORT_SYMBOL_GPL(debugfs_create_x32); @@ -684,10 +690,10 @@ EXPORT_SYMBOL_GPL(debugfs_create_x32); * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_x64(const char *name, umode_t mode, - struct dentry *parent, u64 *value) +void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent, + u64 *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64, + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64, &fops_x64_ro, &fops_x64_wo); } EXPORT_SYMBOL_GPL(debugfs_create_x64); @@ -718,12 +724,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n"); * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_size_t(const char *name, umode_t mode, - struct dentry *parent, size_t *value) +void debugfs_create_size_t(const char *name, umode_t mode, + struct dentry *parent, size_t *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, - &fops_size_t, &fops_size_t_ro, - &fops_size_t_wo); + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t, + &fops_size_t_ro, &fops_size_t_wo); } EXPORT_SYMBOL_GPL(debugfs_create_size_t); @@ -755,12 +760,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, * @value: a pointer to the variable that the file should read to and write * from. */ -struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode, - struct dentry *parent, atomic_t *value) +void debugfs_create_atomic_t(const char *name, umode_t mode, + struct dentry *parent, atomic_t *value) { - return debugfs_create_mode_unsafe(name, mode, parent, value, - &fops_atomic_t, &fops_atomic_t_ro, - &fops_atomic_t_wo); + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t, + &fops_atomic_t_ro, &fops_atomic_t_wo); } EXPORT_SYMBOL_GPL(debugfs_create_atomic_t); @@ -845,10 +849,10 @@ static const struct file_operations fops_bool_wo = { * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_bool(const char *name, umode_t mode, @@ -898,10 +902,10 @@ static const struct file_operations fops_blob = { * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_blob(const char *name, umode_t mode, @@ -1090,10 +1094,10 @@ static const struct file_operations fops_regset32 = { * This function will return a pointer to a dentry if it succeeds. This * pointer must be passed to the debugfs_remove() function when the file is * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be + * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be * returned. * - * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will + * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will * be returned. */ struct dentry *debugfs_create_regset32(const char *name, umode_t mode, @@ -1157,4 +1161,3 @@ struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name, &debugfs_devm_entry_ops); } EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile); - |
