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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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ea81531de2
When translating user space addresses to kernel addresses the follow_table() function had two bugs: - PROT_NONE mappings could be read accessed via the kernel mapping. That is e.g. putting a filename into a user page, then protecting the page with PROT_NONE and afterwards issuing the "open" syscall with a pointer to the filename would incorrectly succeed. - when walking the page tables it used the pgd/pud/pmd/pte primitives which with dynamic page tables give no indication which real level of page tables is being walked (region2, region3, segment or page table). So in case of an exception the translation exception code passed to __handle_fault() is not necessarily correct. This is not really an issue since __handle_fault() doesn't evaluate the code. Only in case of e.g. a SIGBUS this code gets passed to user space. If user space can do something sane with the value is a different question though. To fix these issues don't use any Linux primitives. Only walk the page tables like the hardware would do it, however we leave quite some checks away since we know that we only have full size page tables and each index is within bounds. In theory this should fix all issues... Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> |
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| .. | ||
| delay.c | ||
| div64.c | ||
| Makefile | ||
| mem32.S | ||
| mem64.S | ||
| qrnnd.S | ||
| spinlock.c | ||
| string.c | ||
| uaccess_mvcos.c | ||
| uaccess_pt.c | ||
| uaccess_std.c | ||
| uaccess.h | ||
| ucmpdi2.c | ||
| usercopy.c | ||