mirror of https://gitee.com/openkylin/linux.git
2606b28aab
There's a bunch of failure exits in ffs_fs_mount() with seriously broken recovery logics. Most of that appears to stem from misunderstanding of the ->kill_sb() semantics; unlike ->put_super() it is called for *all* superblocks of given type, no matter how (in)complete the setup had been. ->put_super() is called only if ->s_root is not NULL; any failure prior to setting ->s_root will have the call of ->put_super() skipped. ->kill_sb(), OTOH, awaits every superblock that has come from sget(). Current behaviour of ffs_fs_mount(): We have struct ffs_sb_fill_data data on stack there. We do ffs_dev = functionfs_acquire_dev_callback(dev_name); and store that in data.private_data. Then we call mount_nodev(), passing it ffs_sb_fill() as a callback. That will either fail outright, or manage to call ffs_sb_fill(). There we allocate an instance of struct ffs_data, slap the value of ffs_dev (picked from data.private_data) into ffs->private_data and overwrite data.private_data by storing ffs into an overlapping member (data.ffs_data). Then we store ffs into sb->s_fs_info and attempt to set the rest of the things up (root inode, root dentry, then create /ep0 there). Any of those might fail. Should that happen, we get ffs_fs_kill_sb() called before mount_nodev() returns. If mount_nodev() fails for any reason whatsoever, we proceed to functionfs_release_dev_callback(data.ffs_data); That's broken in a lot of ways. Suppose the thing has failed in allocation of e.g. root inode or dentry. We have functionfs_release_dev_callback(ffs); ffs_data_put(ffs); done by ffs_fs_kill_sb() (ffs accessed via sb->s_fs_info), followed by functionfs_release_dev_callback(ffs); from ffs_fs_mount() (via data.ffs_data). Note that the second functionfs_release_dev_callback() has every chance to be done to freed memory. Suppose we fail *before* root inode allocation. What happens then? ffs_fs_kill_sb() doesn't do anything to ffs (it's either not called at all, or it doesn't have a pointer to ffs stored in sb->s_fs_info). And functionfs_release_dev_callback(data.ffs_data); is called by ffs_fs_mount(), but here we are in nasal daemon country - we are reading from a member of union we'd never stored into. In practice, we'll get what we used to store into the overlapping field, i.e. ffs_dev. And then we get screwed, since we treat it (struct gfs_ffs_obj * in disguise, returned by functionfs_acquire_dev_callback()) as struct ffs_data *, pick what would've been ffs_data ->private_data from it (*well* past the actual end of the struct gfs_ffs_obj - struct ffs_data is much bigger) and poke in whatever it points to. FWIW, there's a minor leak on top of all that in case if ffs_sb_fill() fails on kstrdup() - ffs is obviously forgotten. The thing is, there is no point in playing all those games with union. Just allocate and initialize ffs_data *before* calling mount_nodev() and pass a pointer to it via data.ffs_data. And once it's stored in sb->s_fs_info, clear data.ffs_data, so that ffs_fs_mount() knows that it doesn't need to kill the sucker manually - from that point on we'll have it done by ->kill_sb(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: stable <stable@vger.kernel.org> # 3.3+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| acm_ms.c | ||
| amd5536udc.c | ||
| amd5536udc.h | ||
| at91_udc.c | ||
| at91_udc.h | ||
| atmel_usba_udc.c | ||
| atmel_usba_udc.h | ||
| audio.c | ||
| bcm63xx_udc.c | ||
| cdc2.c | ||
| composite.c | ||
| config.c | ||
| configfs.c | ||
| dbgp.c | ||
| dummy_hcd.c | ||
| epautoconf.c | ||
| ether.c | ||
| f_acm.c | ||
| f_ecm.c | ||
| f_eem.c | ||
| f_fs.c | ||
| f_hid.c | ||
| f_loopback.c | ||
| f_mass_storage.c | ||
| f_midi.c | ||
| f_ncm.c | ||
| f_obex.c | ||
| f_phonet.c | ||
| f_rndis.c | ||
| f_serial.c | ||
| f_sourcesink.c | ||
| f_subset.c | ||
| f_uac1.c | ||
| f_uac2.c | ||
| f_uvc.c | ||
| f_uvc.h | ||
| fotg210-udc.c | ||
| fotg210.h | ||
| fsl_mxc_udc.c | ||
| fsl_qe_udc.c | ||
| fsl_qe_udc.h | ||
| fsl_udc_core.c | ||
| fsl_usb2_udc.h | ||
| functions.c | ||
| fusb300_udc.c | ||
| fusb300_udc.h | ||
| g_ffs.c | ||
| g_zero.h | ||
| gadget_chips.h | ||
| gmidi.c | ||
| goku_udc.c | ||
| goku_udc.h | ||
| hid.c | ||
| inode.c | ||
| lpc32xx_udc.c | ||
| m66592-udc.c | ||
| m66592-udc.h | ||
| mass_storage.c | ||
| multi.c | ||
| mv_u3d.h | ||
| mv_u3d_core.c | ||
| mv_udc.h | ||
| mv_udc_core.c | ||
| ncm.c | ||
| ndis.h | ||
| net2272.c | ||
| net2272.h | ||
| net2280.c | ||
| net2280.h | ||
| nokia.c | ||
| omap_udc.c | ||
| omap_udc.h | ||
| pch_udc.c | ||
| printer.c | ||
| pxa25x_udc.c | ||
| pxa25x_udc.h | ||
| pxa27x_udc.c | ||
| pxa27x_udc.h | ||
| r8a66597-udc.c | ||
| r8a66597-udc.h | ||
| rndis.c | ||
| rndis.h | ||
| s3c-hsotg.c | ||
| s3c-hsotg.h | ||
| s3c-hsudc.c | ||
| s3c2410_udc.c | ||
| s3c2410_udc.h | ||
| serial.c | ||
| storage_common.c | ||
| tcm_usb_gadget.c | ||
| tcm_usb_gadget.h | ||
| u_ecm.h | ||
| u_eem.h | ||
| u_ether.c | ||
| u_ether.h | ||
| u_ether_configfs.h | ||
| u_gether.h | ||
| u_ncm.h | ||
| u_phonet.h | ||
| u_rndis.h | ||
| u_serial.c | ||
| u_serial.h | ||
| u_uac1.c | ||
| u_uac1.h | ||
| udc-core.c | ||
| usbstring.c | ||
| uvc.h | ||
| uvc_queue.c | ||
| uvc_queue.h | ||
| uvc_v4l2.c | ||
| uvc_video.c | ||
| webcam.c | ||
| zero.c | ||