From: Mark Wielaard Date: Tue, 26 Dec 2017 10:52:06 +0000 (+0100) Subject: libdw: New get_uleb128_unchecked to use with already checked Dwarf_Abbrev. X-Git-Tag: elfutils-0.171~87 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bfb2117387eb98eae4f0aace7c32061a27483adc;p=thirdparty%2Felfutils.git libdw: New get_uleb128_unchecked to use with already checked Dwarf_Abbrev. When creating a Dwarf_Abbrev in dwarf_getabbrev (__libdw_getabbrev) we already check it is fully readable from the .debug_abbrev section. So whenever we reread it later using the attrp pointer we don't have to check it again. Introduce get_uleb128_unchecked to use for ulebs we know are safe to read directly. Signed-off-by: Mark Wielaard --- diff --git a/libdw/ChangeLog b/libdw/ChangeLog index 97155de1f..ba9bbe1ab 100644 --- a/libdw/ChangeLog +++ b/libdw/ChangeLog @@ -1,3 +1,13 @@ +2017-12-26 Mark Wielaard + + * memory-access.h (__libdw_get_uleb128_unchecked): New function. + (get_uleb128_unchecked): New define. + * dwarf_child.c (__libdw_find_attr): Use get_uleb128_unchecked to + read attr name and form. + * dwarf_getabbrevattr.c (dwarf_getabbrevattr): Likewise. + * dwarf_getattrs.c (dwarf_getattrs): Likewise. + * dwarf_hasattr.c (dwarf_hasattr): Likewise. + 2017-12-28 Mark Wielaard * dwarf_offdie.c (__libdw_offdie): Check sectiondata exists. diff --git a/libdw/dwarf_child.c b/libdw/dwarf_child.c index cc95fb3fa..248338eb2 100644 --- a/libdw/dwarf_child.c +++ b/libdw/dwarf_child.c @@ -1,5 +1,5 @@ /* Return child of current DIE. - Copyright (C) 2003-2011, 2014 Red Hat, Inc. + Copyright (C) 2003-2011, 2014, 2017 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper , 2003. @@ -43,36 +43,27 @@ internal_function __libdw_find_attr (Dwarf_Die *die, unsigned int search_name, unsigned int *codep, unsigned int *formp) { - Dwarf *dbg = die->cu->dbg; const unsigned char *readp; /* Find the abbreviation entry. */ Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, &readp); if (unlikely (abbrevp == DWARF_END_ABBREV)) { - invalid_dwarf: __libdw_seterrno (DWARF_E_INVALID_DWARF); return NULL; } - /* Search the name attribute. */ - unsigned char *const endp - = ((unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf - + dbg->sectiondata[IDX_debug_abbrev]->d_size); - + /* Search the name attribute. Attribute has been checked when + Dwarf_Abbrev was created, we can read unchecked. */ const unsigned char *attrp = abbrevp->attrp; while (1) { /* Get attribute name and form. */ - if (unlikely (attrp >= endp)) - goto invalid_dwarf; unsigned int attr_name; - get_uleb128 (attr_name, attrp, endp); + get_uleb128_unchecked (attr_name, attrp); - if (unlikely (attrp >= endp)) - goto invalid_dwarf; unsigned int attr_form; - get_uleb128 (attr_form, attrp, endp); + get_uleb128_unchecked (attr_form, attrp); /* We can stop if we found the attribute with value zero. */ if (attr_name == 0 && attr_form == 0) diff --git a/libdw/dwarf_getabbrevattr.c b/libdw/dwarf_getabbrevattr.c index 3b4da99ce..57fe36377 100644 --- a/libdw/dwarf_getabbrevattr.c +++ b/libdw/dwarf_getabbrevattr.c @@ -1,5 +1,5 @@ /* Get specific attribute of abbreviation. - Copyright (C) 2003, 2004, 2005, 2014 Red Hat, Inc. + Copyright (C) 2003, 2004, 2005, 2014, 2017 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper , 2003. @@ -53,10 +53,10 @@ dwarf_getabbrevattr (Dwarf_Abbrev *abbrev, size_t idx, unsigned int *namep, { start_attrp = attrp; - /* Attribute code and form are encoded as ULEB128 values.i - XXX We have no way to bounds check. */ - get_uleb128 (name, attrp, attrp + len_leb128 (name)); - get_uleb128 (form, attrp, attrp + len_leb128 (form)); + /* Attribute code and form are encoded as ULEB128 values. + Already checked when Dwarf_Abbrev was created, read unchecked. */ + get_uleb128_unchecked (name, attrp); + get_uleb128_unchecked (form, attrp); /* If both values are zero the index is out of range. */ if (name == 0 && form == 0) diff --git a/libdw/dwarf_getattrs.c b/libdw/dwarf_getattrs.c index 0da8b5ba0..7f55fafcb 100644 --- a/libdw/dwarf_getattrs.c +++ b/libdw/dwarf_getattrs.c @@ -1,5 +1,5 @@ /* Get attributes of the DIE. - Copyright (C) 2004, 2005, 2008, 2009, 2014 Red Hat, Inc. + Copyright (C) 2004, 2005, 2008, 2009, 2014, 2017 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper , 2004. @@ -51,7 +51,6 @@ dwarf_getattrs (Dwarf_Die *die, int (*callback) (Dwarf_Attribute *, void *), if (unlikely (abbrevp == DWARF_END_ABBREV)) { - invalid_dwarf: __libdw_seterrno (DWARF_E_INVALID_DWARF); return -1l; } @@ -61,24 +60,15 @@ dwarf_getattrs (Dwarf_Die *die, int (*callback) (Dwarf_Attribute *, void *), const unsigned char *const offset_attrp = abbrevp->attrp + offset; /* Go over the list of attributes. */ - Dwarf *dbg = die->cu->dbg; - const unsigned char *endp; - endp = ((const unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf - + dbg->sectiondata[IDX_debug_abbrev]->d_size); while (1) { - /* Are we still in bounds? */ - if (unlikely (attrp >= endp)) - goto invalid_dwarf; - - /* Get attribute name and form. */ + /* Get attribute name and form. Dwarf_Abbrev was checked when + created, so we can read unchecked. */ Dwarf_Attribute attr; const unsigned char *remembered_attrp = attrp; - get_uleb128 (attr.code, attrp, endp); - if (unlikely (attrp >= endp)) - goto invalid_dwarf; - get_uleb128 (attr.form, attrp, endp); + get_uleb128_unchecked (attr.code, attrp); + get_uleb128_unchecked (attr.form, attrp); /* We can stop if we found the attribute with value zero. */ if (attr.code == 0 && attr.form == 0) diff --git a/libdw/dwarf_hasattr.c b/libdw/dwarf_hasattr.c index 2bb8dc826..90b333e62 100644 --- a/libdw/dwarf_hasattr.c +++ b/libdw/dwarf_hasattr.c @@ -1,5 +1,5 @@ /* Check whether given DIE has specific attribute. - Copyright (C) 2003, 2005, 2014 Red Hat, Inc. + Copyright (C) 2003, 2005, 2014, 2017 Red Hat, Inc. This file is part of elfutils. Written by Ulrich Drepper , 2003. @@ -45,32 +45,20 @@ dwarf_hasattr (Dwarf_Die *die, unsigned int search_name) Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, NULL); if (unlikely (abbrevp == DWARF_END_ABBREV)) { - invalid_dwarf: __libdw_seterrno (DWARF_E_INVALID_DWARF); return 0; } - Dwarf *dbg = die->cu->dbg; - - /* Search the name attribute. */ - unsigned char *const endp - = ((unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf - + dbg->sectiondata[IDX_debug_abbrev]->d_size); - + /* Search the name attribute. Dwarf_Abbrev was checked when created, + so we can read unchecked here. */ const unsigned char *attrp = abbrevp->attrp; while (1) { - /* Are we still in bounds? This test needs to be refined. */ - if (unlikely (attrp >= endp)) - goto invalid_dwarf; - /* Get attribute name and form. */ unsigned int attr_name; - get_uleb128 (attr_name, attrp, endp); + get_uleb128_unchecked (attr_name, attrp); unsigned int attr_form; - if (unlikely (attrp >= endp)) - goto invalid_dwarf; - get_uleb128 (attr_form, attrp, endp); + get_uleb128_unchecked (attr_form, attrp); /* We can stop if we found the attribute with value zero. */ if (attr_name == 0 || attr_form == 0) diff --git a/libdw/memory-access.h b/libdw/memory-access.h index afb651fce..ed68bdb9f 100644 --- a/libdw/memory-access.h +++ b/libdw/memory-access.h @@ -87,8 +87,26 @@ __libdw_get_uleb128 (const unsigned char **addrp, const unsigned char *end) return UINT64_MAX; } +static inline uint64_t +__libdw_get_uleb128_unchecked (const unsigned char **addrp) +{ + uint64_t acc = 0; + + /* Unroll the first step to help the compiler optimize + for the common single-byte case. */ + get_uleb128_step (acc, *addrp, 0); + + const size_t max = len_leb128 (uint64_t); + for (size_t i = 1; i < max; ++i) + get_uleb128_step (acc, *addrp, i); + /* Other implementations set VALUE to UINT_MAX in this + case. So we better do this as well. */ + return UINT64_MAX; +} + /* Note, addr needs to me smaller than end. */ #define get_uleb128(var, addr, end) ((var) = __libdw_get_uleb128 (&(addr), end)) +#define get_uleb128_unchecked(var, addr) ((var) = __libdw_get_uleb128_unchecked (&(addr))) /* The signed case is similar, but we sign-extend the result. */