From 2ba6bef9714cdb3a551868562a86cfea61042be1 Mon Sep 17 00:00:00 2001 From: avg Date: Thu, 19 Oct 2017 08:00:34 +0000 Subject: [PATCH] MFC r324311: sysctl-s in a module should be accessible only when the module is initialized Sponsored by: Panzura git-svn-id: svn://svn.freebsd.org/base/stable/10@324749 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/kern/kern_linker.c | 37 ++++++++++++++++++++++++++++++++----- sys/kern/kern_sysctl.c | 35 ++++++++++++++++++++++++++++++++++- sys/sys/sysctl.h | 3 +++ 3 files changed, 69 insertions(+), 6 deletions(-) diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c index ca8c10aa8..a0dbde341 100644 --- a/sys/kern/kern_linker.c +++ b/sys/kern/kern_linker.c @@ -285,7 +285,7 @@ linker_file_sysuninit(linker_file_t lf) } static void -linker_file_register_sysctls(linker_file_t lf) +linker_file_register_sysctls(linker_file_t lf, bool enable) { struct sysctl_oid **start, **stop, **oidp; @@ -295,13 +295,39 @@ linker_file_register_sysctls(linker_file_t lf) sx_assert(&kld_sx, SA_XLOCKED); + if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0) + return; + + sx_xunlock(&kld_sx); + sysctl_lock(); + for (oidp = start; oidp < stop; oidp++) { + if (enable) + sysctl_register_oid(*oidp); + else + sysctl_register_disabled_oid(*oidp); + } + sysctl_unlock(); + sx_xlock(&kld_sx); +} + +static void +linker_file_enable_sysctls(linker_file_t lf) +{ + struct sysctl_oid **start, **stop, **oidp; + + KLD_DPF(FILE, + ("linker_file_enable_sysctls: enable SYSCTLs for %s\n", + lf->filename)); + + sx_assert(&kld_sx, SA_XLOCKED); + if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0) return; sx_xunlock(&kld_sx); sysctl_lock(); for (oidp = start; oidp < stop; oidp++) - sysctl_register_oid(*oidp); + sysctl_enable_oid(*oidp); sysctl_unlock(); sx_xlock(&kld_sx); } @@ -427,7 +453,7 @@ linker_load_file(const char *filename, linker_file_t *result) return (error); } modules = !TAILQ_EMPTY(&lf->modules); - linker_file_register_sysctls(lf); + linker_file_register_sysctls(lf, false); linker_file_sysinit(lf); lf->flags |= LINKER_FILE_LINKED; @@ -440,6 +466,7 @@ linker_load_file(const char *filename, linker_file_t *result) linker_file_unload(lf, LINKER_UNLOAD_FORCE); return (ENOEXEC); } + linker_file_enable_sysctls(lf); EVENTHANDLER_INVOKE(kld_load, lf); *result = lf; return (0); @@ -686,8 +713,8 @@ linker_file_unload(linker_file_t file, int flags) */ if (file->flags & LINKER_FILE_LINKED) { file->flags &= ~LINKER_FILE_LINKED; - linker_file_sysuninit(file); linker_file_unregister_sysctls(file); + linker_file_sysuninit(file); } TAILQ_REMOVE(&linker_files, file, link); @@ -1618,7 +1645,7 @@ linker_preload(void *arg) if (linker_file_lookup_set(lf, "sysinit_set", &si_start, &si_stop, NULL) == 0) sysinit_add(si_start, si_stop); - linker_file_register_sysctls(lf); + linker_file_register_sysctls(lf, true); lf->flags |= LINKER_FILE_LINKED; continue; fail: diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c index 27429facd..85a198296 100644 --- a/sys/kern/kern_sysctl.c +++ b/sys/kern/kern_sysctl.c @@ -225,6 +225,37 @@ sysctl_register_oid(struct sysctl_oid *oidp) SLIST_INSERT_HEAD(parent, oidp, oid_link); } +void +sysctl_register_disabled_oid(struct sysctl_oid *oidp) +{ + + /* + * Mark the leaf as dormant if it's not to be immediately enabled. + * We do not disable nodes as they can be shared between modules + * and it is always safe to access a node. + */ + KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0, + ("internal flag is set in oid_kind")); + if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) + oidp->oid_kind |= CTLFLAG_DORMANT; + sysctl_register_oid(oidp); +} + +void +sysctl_enable_oid(struct sysctl_oid *oidp) +{ + + SYSCTL_ASSERT_XLOCKED(); + if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) { + KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) == 0, + ("sysctl node is marked as dormant")); + return; + } + KASSERT((oidp->oid_kind & CTLFLAG_DORMANT) != 0, + ("enabling already enabled sysctl oid")); + oidp->oid_kind &= ~CTLFLAG_DORMANT; +} + void sysctl_unregister_oid(struct sysctl_oid *oidp) { @@ -768,7 +799,7 @@ sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen, *next = oidp->oid_number; *oidpp = oidp; - if (oidp->oid_kind & CTLFLAG_SKIP) + if ((oidp->oid_kind & (CTLFLAG_SKIP | CTLFLAG_DORMANT)) != 0) continue; if (!namelen) { @@ -1420,6 +1451,8 @@ sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid, } lsp = SYSCTL_CHILDREN(oid); } else if (indx == namelen) { + if ((oid->oid_kind & CTLFLAG_DORMANT) != 0) + return (ENOENT); *noid = oid; if (nindx != NULL) *nindx = indx; diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h index f159424f1..87200f608 100644 --- a/sys/sys/sysctl.h +++ b/sys/sys/sysctl.h @@ -77,6 +77,7 @@ struct ctlname { #define CTLFLAG_RD 0x80000000 /* Allow reads of variable */ #define CTLFLAG_WR 0x40000000 /* Allow writes to the variable */ #define CTLFLAG_RW (CTLFLAG_RD|CTLFLAG_WR) +#define CTLFLAG_DORMANT 0x20000000 /* This sysctl is not active yet */ #define CTLFLAG_ANYBODY 0x10000000 /* All users can set this var */ #define CTLFLAG_SECURE 0x08000000 /* Permit set only if securelevel<=0 */ #define CTLFLAG_PRISON 0x04000000 /* Prisoned roots can fiddle */ @@ -205,6 +206,8 @@ int sysctl_dpcpu_quad(SYSCTL_HANDLER_ARGS); * These functions are used to add/remove an oid from the mib. */ void sysctl_register_oid(struct sysctl_oid *oidp); +void sysctl_register_disabled_oid(struct sysctl_oid *oidp); +void sysctl_enable_oid(struct sysctl_oid *oidp); void sysctl_unregister_oid(struct sysctl_oid *oidp); /* Declare a static oid to allow child oids to be added to it. */ -- 2.45.0