| Message ID | 20240318103003.484602-1-kconsul@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] slof/fs/packages/disk-label.fs: improve checking for DOS boot partitions | expand |
On 18/03/2024 11.30, Kautuk Consul wrote: > While testing with a qcow2 with a DOS boot partition it was found that > when we set the logical_block_size in the guest XML to >512 then the > boot would fail ... > diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs > index 661c6b0..2630701 100644 > --- a/slof/fs/packages/disk-label.fs > +++ b/slof/fs/packages/disk-label.fs > @@ -132,11 +132,16 @@ CONSTANT /gpt-part-entry > debug-disk-label? IF dup ." actual=" .d cr THEN > ; > > -\ read sector to array "block" > -: read-sector ( sector-number -- ) > +\ read sector to array "block" and return actual bytes read > +: read-sector-ret ( sector-number -- actual-bytes ) > \ block-size is 0x200 on disks, 0x800 on cdrom drives > block-size * 0 seek drop \ seek to sector > - block block-size read drop \ read sector > + block block-size read \ read sector > +; > + > +\ read sector to array "block" > +: read-sector ( sector-number -- ) > + read-sector-ret drop > ; > > : (.part-entry) ( part-entry ) > @@ -204,7 +209,8 @@ CONSTANT /gpt-part-entry > part-entry>sector-offset l@-le ( current sector ) > dup to part-start to lpart-start ( current ) I just noticed that according to the stack comment above, there is a "current" item on the stack... > BEGIN > - part-start read-sector \ read EBR > + part-start read-sector-ret \ read EBR > + block-size < IF UNLOOP 0 EXIT THEN ... which doesn't get dropped here before the EXIT ? Is the stack still right after this function exited early? > 1 partition>start-sector IF > \ ." Logical Partition found at " part-start .d cr > 1+ > @@ -279,6 +285,7 @@ CONSTANT /gpt-part-entry > THEN > > count-dos-logical-partitions TO dos-logical-partitions > + dos-logical-partitions 0= IF false EXIT THEN > > debug-disk-label? IF > ." Found " dos-logical-partitions .d ." logical partitions" cr > @@ -352,6 +359,7 @@ CONSTANT /gpt-part-entry > no-mbr? IF drop FALSE EXIT THEN \ read MBR and check for DOS disk-label magic > > count-dos-logical-partitions TO dos-logical-partitions > + dos-logical-partitions 0= IF 0 EXIT THEN Similar question here, what about the "addr" stack item? Shouldn't it be dropped first? Thomas PS: I'm still having trouble receiving your mail, I just discovered v2 on patchwork and downloaded it from there...
Hi, On 2024-03-26 15:45:46, Thomas Huth wrote: > On 18/03/2024 11.30, Kautuk Consul wrote: > > While testing with a qcow2 with a DOS boot partition it was found that > > when we set the logical_block_size in the guest XML to >512 then the > > boot would fail > ... > > diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs > > index 661c6b0..2630701 100644 > > --- a/slof/fs/packages/disk-label.fs > > +++ b/slof/fs/packages/disk-label.fs > > @@ -132,11 +132,16 @@ CONSTANT /gpt-part-entry > > debug-disk-label? IF dup ." actual=" .d cr THEN > > ; > > -\ read sector to array "block" > > -: read-sector ( sector-number -- ) > > +\ read sector to array "block" and return actual bytes read > > +: read-sector-ret ( sector-number -- actual-bytes ) > > \ block-size is 0x200 on disks, 0x800 on cdrom drives > > block-size * 0 seek drop \ seek to sector > > - block block-size read drop \ read sector > > + block block-size read \ read sector > > +; > > + > > +\ read sector to array "block" > > +: read-sector ( sector-number -- ) > > + read-sector-ret drop > > ; > > : (.part-entry) ( part-entry ) > > @@ -204,7 +209,8 @@ CONSTANT /gpt-part-entry > > part-entry>sector-offset l@-le ( current sector ) > > dup to part-start to lpart-start ( current ) > > I just noticed that according to the stack comment above, there is a > "current" item on the stack... > > > BEGIN > > - part-start read-sector \ read EBR > > + part-start read-sector-ret \ read EBR > > + block-size < IF UNLOOP 0 EXIT THEN > > ... which doesn't get dropped here before the EXIT ? Is the stack still > right after this function exited early? Thanks for catching this. I didn't notice this as I sent this v2 in a hurry. > > > 1 partition>start-sector IF > > \ ." Logical Partition found at " part-start .d cr > > 1+ > > @@ -279,6 +285,7 @@ CONSTANT /gpt-part-entry > > THEN > > count-dos-logical-partitions TO dos-logical-partitions > > + dos-logical-partitions 0= IF false EXIT THEN > > debug-disk-label? IF > > ." Found " dos-logical-partitions .d ." logical partitions" cr > > @@ -352,6 +359,7 @@ CONSTANT /gpt-part-entry > > no-mbr? IF drop FALSE EXIT THEN \ read MBR and check for DOS disk-label magic > > count-dos-logical-partitions TO dos-logical-partitions > > + dos-logical-partitions 0= IF 0 EXIT THEN > > Similar question here, what about the "addr" stack item? Shouldn't it be > dropped first? Yes. Will take a look at this too. Thanks! I will make these both changes and test them out before sending out a v3. > > Thomas > > > PS: I'm still having trouble receiving your mail, I just discovered v2 on > patchwork and downloaded it from there... Okay I will check everything from my side to see if everything is in order. >
Hi Thomas, I just sent out the v3. Can you please review that ? Thanks again! :-)
diff --git a/slof/fs/packages/disk-label.fs b/slof/fs/packages/disk-label.fs index 661c6b0..2630701 100644 --- a/slof/fs/packages/disk-label.fs +++ b/slof/fs/packages/disk-label.fs @@ -132,11 +132,16 @@ CONSTANT /gpt-part-entry debug-disk-label? IF dup ." actual=" .d cr THEN ; -\ read sector to array "block" -: read-sector ( sector-number -- ) +\ read sector to array "block" and return actual bytes read +: read-sector-ret ( sector-number -- actual-bytes ) \ block-size is 0x200 on disks, 0x800 on cdrom drives block-size * 0 seek drop \ seek to sector - block block-size read drop \ read sector + block block-size read \ read sector +; + +\ read sector to array "block" +: read-sector ( sector-number -- ) + read-sector-ret drop ; : (.part-entry) ( part-entry ) @@ -204,7 +209,8 @@ CONSTANT /gpt-part-entry part-entry>sector-offset l@-le ( current sector ) dup to part-start to lpart-start ( current ) BEGIN - part-start read-sector \ read EBR + part-start read-sector-ret \ read EBR + block-size < IF UNLOOP 0 EXIT THEN 1 partition>start-sector IF \ ." Logical Partition found at " part-start .d cr 1+ @@ -279,6 +285,7 @@ CONSTANT /gpt-part-entry THEN count-dos-logical-partitions TO dos-logical-partitions + dos-logical-partitions 0= IF false EXIT THEN debug-disk-label? IF ." Found " dos-logical-partitions .d ." logical partitions" cr @@ -352,6 +359,7 @@ CONSTANT /gpt-part-entry no-mbr? IF drop FALSE EXIT THEN \ read MBR and check for DOS disk-label magic count-dos-logical-partitions TO dos-logical-partitions + dos-logical-partitions 0= IF 0 EXIT THEN debug-disk-label? IF ." Found " dos-logical-partitions .d ." logical partitions" cr
While testing with a qcow2 with a DOS boot partition it was found that when we set the logical_block_size in the guest XML to >512 then the boot would fail in the following interminable loop: <SNIP> Trying to load: from: /pci@800000020000000/scsi@3 ... virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! </SNIP> Change the count-dos-logical-partitions Forth subroutine and the Forth subroutines calling count-dos-logical-partitions to check for this access beyond end of device error. After making the above changes, it fails properly with the correct error message as follows: <SNIP> Trying to load: from: /pci@800000020000000/scsi@3 ... virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! virtioblk_transfer: Access beyond end of device! E3404: Not a bootable device! E3407: Load failed Type 'boot' and press return to continue booting the system. Type 'reset-all' and press return to reboot the system. Ready! 0 > </SNIP> Signed-off-by: Kautuk Consul <kconsul@linux.vnet.ibm.com> --- slof/fs/packages/disk-label.fs | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)