From 3f53fe2e966bdc234069770846890cd26bd5cebf Mon Sep 17 00:00:00 2001 From: Alexander Kamensky Date: Sun, 27 Aug 2023 13:53:02 -0700 Subject: [PATCH] aarch64: introduce user_rootpgt param to read user space memory Commit dfa510fec6128d22e1a6d0ce5774472110bcf59c (aarch64: Fix bottom VA range translation in Linux) introduced METH_UPGT for user-space bottom addresses that cover TTBR0_EL1 addresses. Unfortunately, it breaks the case where root pgt from user land process was passed and used to translate vmcore memory to get specified user land process virtual memory reads. libkdumpfile based gdbserver was using such functionality before: https://github.com/AlexanderKamensky/libkdumpfile/tree/new_20230805/gdbserver#process This patch introduces new keyword parameter user_rootpgt for System.os_init, that would be filled into METH_UPGT method param.pgt.root. As result any kernel or user land virtual addresses will be readable. Signed-off-by: Alexander Kamensky --- include/libkdumpfile/addrxlat.h.in | 13 +++++++++++++ python/addrxlat.c | 14 +++++++++++--- src/addrxlat/aarch64.c | 4 ++++ src/addrxlat/addrxlat-priv.h | 1 + src/addrxlat/sys.c | 4 ++++ 5 files changed, 33 insertions(+), 3 deletions(-) diff --git a/include/libkdumpfile/addrxlat.h.in b/include/libkdumpfile/addrxlat.h.in index c5f562d6..67a31df0 100644 --- a/include/libkdumpfile/addrxlat.h.in +++ b/include/libkdumpfile/addrxlat.h.in @@ -829,6 +829,11 @@ typedef enum _addrxlat_optidx { */ ADDRXLAT_OPT_rootpgt, + /** User land root page table address. Used *only* in aarch64 case. + * Type: full address + */ + ADDRXLAT_OPT_user_rootpgt, + /** Xen p2m root machine frame number. * Type: address */ @@ -928,6 +933,14 @@ addrxlat_opt_rootpgt(addrxlat_opt_t *opt, const addrxlat_fulladdr_t *val) opt->val.fulladdr = *val; } +/** Helper to set @xref ADDRXLAT_OPT_user_rootpgt in a type-safe manner. */ +static inline void +addrxlat_opt_user_rootpgt(addrxlat_opt_t *opt, const addrxlat_fulladdr_t *val) +{ + opt->idx = ADDRXLAT_OPT_user_rootpgt; + opt->val.fulladdr = *val; +} + /** Helper to set @xref ADDRXLAT_OPT_xen_p2m_mfn in a type-safe manner. */ static inline void addrxlat_opt_xen_p2m_mfn(addrxlat_opt_t *opt, unsigned long val) diff --git a/python/addrxlat.c b/python/addrxlat.c index f52003d4..a810e9f1 100644 --- a/python/addrxlat.c +++ b/python/addrxlat.c @@ -4312,13 +4312,14 @@ sys_os_init(PyObject *_self, PyObject *args, PyObject *kwargs) "page_shift", "phys_base", "rootpgt", + "user_rootpgt", "xen_p2m_mfn", "xen_xlat", NULL }; PyObject *ctxobj; PyObject *arch, *type, *ver, *page_shift, *phys_base, - *rootpgt, *xen_p2m_mfn, *xen_xlat, *phys_bits, *virt_bits; + *rootpgt, *user_rootpgt, *xen_p2m_mfn, *xen_xlat, *phys_bits, *virt_bits; addrxlat_ctx_t *ctx; addrxlat_opt_t opts[ADDRXLAT_OPT_NUM], *p; addrxlat_status status; @@ -4326,9 +4327,9 @@ sys_os_init(PyObject *_self, PyObject *args, PyObject *kwargs) arch = type = ver = page_shift = phys_base = rootpgt = xen_p2m_mfn = xen_xlat = phys_bits = virt_bits = Py_None; if (!PyArg_ParseTupleAndKeywords( - args, kwargs, "O|OOOOOOOOOO:os_init", keywords, + args, kwargs, "O|OOOOOOOOOOO:os_init", keywords, &ctxobj, &arch, &type, &ver, &phys_bits, &virt_bits, - &page_shift, &phys_base, &rootpgt, &xen_p2m_mfn, + &page_shift, &phys_base, &rootpgt, &user_rootpgt, &xen_p2m_mfn, &xen_xlat)) return NULL; @@ -4394,6 +4395,13 @@ sys_os_init(PyObject *_self, PyObject *args, PyObject *kwargs) addrxlat_opt_rootpgt(p, faddr); ++p; } + if (user_rootpgt != Py_None) { + addrxlat_fulladdr_t *faddr = fulladdr_AsPointer(user_rootpgt); + if (!faddr) + return NULL; + addrxlat_opt_user_rootpgt(p, faddr); + ++p; + } if (xen_p2m_mfn != Py_None) { addrxlat_opt_xen_p2m_mfn( p, Number_AsUnsignedLongLong(xen_p2m_mfn)); diff --git a/src/addrxlat/aarch64.c b/src/addrxlat/aarch64.c index cf7499be..503c62aa 100644 --- a/src/addrxlat/aarch64.c +++ b/src/addrxlat/aarch64.c @@ -404,6 +404,10 @@ map_linux_aarch64(struct os_init_data *ctl) return status; } + meth = &ctl->sys->meth[ADDRXLAT_SYS_METH_UPGT]; + if (opt_isset(ctl->popt, user_rootpgt)) + meth->param.pgt.root = ctl->popt.user_rootpgt; + status = sys_set_physmaps(ctl, PHYSADDR_MASK); if (status != ADDRXLAT_OK) return status; diff --git a/src/addrxlat/addrxlat-priv.h b/src/addrxlat/addrxlat-priv.h index a27a3f5b..9d7cabac 100644 --- a/src/addrxlat/addrxlat-priv.h +++ b/src/addrxlat/addrxlat-priv.h @@ -414,6 +414,7 @@ struct parsed_opts { unsigned long page_shift; /**< Value of OPT_page_shift. */ addrxlat_addr_t phys_base; /**< Value of OPT_phys_base. */ addrxlat_fulladdr_t rootpgt; /**< Value of OPT_rootpgt. */ + addrxlat_fulladdr_t user_rootpgt; /**< Value of OPT_user_rootpgt. */ unsigned long xen_p2m_mfn; /**< Value of OPT_xen_p2m_mfn. */ bool xen_xlat; /**< Value of OPT_xen_xlat. */ }; diff --git a/src/addrxlat/sys.c b/src/addrxlat/sys.c index 4f6e068c..17ac3461 100644 --- a/src/addrxlat/sys.c +++ b/src/addrxlat/sys.c @@ -121,6 +121,10 @@ parse_opt(struct parsed_opts *popt, const addrxlat_opt_t *opt) popt->rootpgt = opt->val.fulladdr; break; + case ADDRXLAT_OPT_user_rootpgt: + popt->user_rootpgt = opt->val.fulladdr; + break; + case ADDRXLAT_OPT_xen_p2m_mfn: popt->xen_p2m_mfn = opt->val.num; break;