devicemodel: hw: pci: gvt: Fix out of bounds error #8118
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
hw/pci/gvt.c:263:41: error: array subscript 257 is above array bounds of ‘uint8_t[256]’ {aka ‘unsigned char[256]’} [-Werror=array-bounds]
263 | gvt->host_config[cap_ptr + 4]);
| ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
hw/pci/gvt.c:48:17: note: while referencing ‘host_config’
48 | uint8_t host_config[PCI_REGMAX+1];
| ^~~~~~~~~~~
With the additional condition cap_ptr < PCI_REGMAX - 16 it is ensured
that we never read config data from places we shouldn't read from.
12 (offset) + 4 (pci_set_cfgdata32) = 16
I would consider this a workaround that gets the job done for
now. However with this approach we can miss the last capabilities in
some edge cases.
Tracked-On: projectacrn#8116
Signed-off-by: Marius Rodi <[email protected]>
ghost
requested a review
from 
|
Can one of the admins verify this patch? |
|
As stated, this fix is more of a workaround. I don't have the time to do this the right way currently. Maybe someone else can have a deeper look into this? |
|
start to run premerge test |
|
@ywan170 could you please review this PR? |
ywan170
reviewed
Sep 22, 2022
|
|
||
| 12 (offset) + 4 (pci_set_cfgdata32) = 16 | ||
| */ | ||
| while (cap_ptr != 0 && cap_ptr < PCI_REGMAX - 16) { |
There was a problem hiding this comment.
Should we change the pci_set_cfgdata32 to pci_set_cfgdata8. And if the cap_ptr != 0 but exceeds the "PCI_REGMAX - 16" then print some warning logs as some capabilities are lost.
@yakuizhao to comment
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
With the additional condition
cap_ptr < PCI_REGMAX - 16it is ensured that we never read config data from places we shouldn't read from.12 (offset) + 4 (pci_set_cfgdata32) = 16
I would consider this a workaround that gets the job done for now. However with this approach we can miss the last capabilities in some edge cases.
Tracked-On: #8116
Signed-off-by: Marius Rodi [email protected]