Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Jul 16, 2015, at 9:19 AM, Stefan Hajnoczi wrote: On Thu, Jul 09, 2015 at 10:02:26AM -0400, Programmingkid wrote: On Jul 9, 2015, at 6:52 AM, Stefan Hajnoczi wrote: On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. Yeah, that should have been done. Did you see any issues with the code? QEMU shouldn't silently open a different file than the one given by the user. The user should give the exact device file they want. If there is magic behavior it needs to be documented, but I don't see a reason why that's necessary in the case of device files. I think you are reviewing an older patch. The newest one doesn't do that. QEMU shouldn't mount/unmount the CD-ROM. atexit(3) doesn't handle crashes or abort(). Users may be confused to find their CD-ROM unmounted in those cases and would see this as a bug. Instead we should refuse mounted CD-ROMs so the user understands that block-level access requires them to unmount first. That can be done. It just wouldn't be as user friendly as having QEMU do it for the user :( The strcpy/sprintf usage in this patch is unsafe and can lead to buffer overflow, for example in the case of generating command-lines. The command-line buffer is only MAXPATHLEN so prepending the command to the filename could exceed the buffer size. There is also a buffer overflow in the array of devices that need to be mounted. What happens if there are more than 7 devices? Ok. Will correct this issue.
Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Thu, Jul 09, 2015 at 10:02:26AM -0400, Programmingkid wrote: On Jul 9, 2015, at 6:52 AM, Stefan Hajnoczi wrote: On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. Yeah, that should have been done. Did you see any issues with the code? QEMU shouldn't silently open a different file than the one given by the user. The user should give the exact device file they want. If there is magic behavior it needs to be documented, but I don't see a reason why that's necessary in the case of device files. QEMU shouldn't mount/unmount the CD-ROM. atexit(3) doesn't handle crashes or abort(). Users may be confused to find their CD-ROM unmounted in those cases and would see this as a bug. Instead we should refuse mounted CD-ROMs so the user understands that block-level access requires them to unmount first. The strcpy/sprintf usage in this patch is unsafe and can lead to buffer overflow, for example in the case of generating command-lines. The command-line buffer is only MAXPATHLEN so prepending the command to the filename could exceed the buffer size. There is also a buffer overflow in the array of devices that need to be mounted. What happens if there are more than 7 devices? pgpzWeEYBeNpv.pgp Description: PGP signature
Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Thu, Jul 16, 2015 at 6:26 PM, Programmingkid programmingk...@gmail.com wrote: On Jul 16, 2015, at 9:19 AM, Stefan Hajnoczi wrote: On Thu, Jul 09, 2015 at 10:02:26AM -0400, Programmingkid wrote: On Jul 9, 2015, at 6:52 AM, Stefan Hajnoczi wrote: On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. Yeah, that should have been done. Did you see any issues with the code? QEMU shouldn't silently open a different file than the one given by the user. The user should give the exact device file they want. If there is magic behavior it needs to be documented, but I don't see a reason why that's necessary in the case of device files. I think you are reviewing an older patch. The newest one doesn't do that. I don't see a more recent patch on the mailing list. What is the Message-Id of your latest patch email?
Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Jul 16, 2015, at 3:43 PM, Stefan Hajnoczi wrote: On Thu, Jul 16, 2015 at 6:26 PM, Programmingkid programmingk...@gmail.com wrote: On Jul 16, 2015, at 9:19 AM, Stefan Hajnoczi wrote: On Thu, Jul 09, 2015 at 10:02:26AM -0400, Programmingkid wrote: On Jul 9, 2015, at 6:52 AM, Stefan Hajnoczi wrote: On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. Yeah, that should have been done. Did you see any issues with the code? QEMU shouldn't silently open a different file than the one given by the user. The user should give the exact device file they want. If there is magic behavior it needs to be documented, but I don't see a reason why that's necessary in the case of device files. I think you are reviewing an older patch. The newest one doesn't do that. I don't see a more recent patch on the mailing list. What is the Message-Id of your latest patch email? Since I will be uploading a new patch shortly, it doesn't matter anymore.
Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Jul 9, 2015, at 6:52 AM, Stefan Hajnoczi wrote: On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. Yeah, that should have been done. Did you see any issues with the code?
Re: [Qemu-devel] [Qemu-block] [PATCH] raw-posix.c: Make physical devices usable in QEMU
On Tue, Jul 07, 2015 at 01:33:23PM -0400, Programmingkid wrote: Make physical devices like a USB flash drive or a CDROM drive work in QEMU. With this patch I can use a USB flash drive like a hard drive. Before this patch, QEMU would just quit with a message like resource busy. The commit message and the description are missing on Mac OS X. It should be clear right away that this applies to Mac only. This works fine on Linux and probably other host OSes. pgpipEVvzvwNN.pgp Description: PGP signature
