diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/x86/dl-prop.h | 51 | ||||
| -rw-r--r-- | sysdeps/x86/link_map.h | 9 |
2 files changed, 46 insertions, 14 deletions
diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h index 26c3131ac5..9ab890d12b 100644 --- a/sysdeps/x86/dl-prop.h +++ b/sysdeps/x86/dl-prop.h @@ -49,6 +49,10 @@ _dl_process_cet_property_note (struct link_map *l, const ElfW(Addr) align) { #if CET_ENABLED + /* Skip if we have seen a NT_GNU_PROPERTY_TYPE_0 note before. */ + if (l->l_cet != lc_unknown) + return; + /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in 32-bit objects and to 8 bytes in 64-bit objects. Skip notes with incorrect alignment. */ @@ -57,6 +61,9 @@ _dl_process_cet_property_note (struct link_map *l, const ElfW(Addr) start = (ElfW(Addr)) note; + unsigned int feature_1 = 0; + unsigned int last_type = 0; + while ((ElfW(Addr)) (note + 1) - start < size) { /* Find the NT_GNU_PROPERTY_TYPE_0 note. */ @@ -64,10 +71,18 @@ _dl_process_cet_property_note (struct link_map *l, && note->n_type == NT_GNU_PROPERTY_TYPE_0 && memcmp (note + 1, "GNU", 4) == 0) { + /* Stop if we see more than one GNU property note which may + be generated by the older linker. */ + if (l->l_cet != lc_unknown) + return; + + /* Check CET status now. */ + l->l_cet = lc_none; + /* Check for invalid property. */ if (note->n_descsz < 8 || (note->n_descsz % sizeof (ElfW(Addr))) != 0) - break; + return; /* Start and end of property array. */ unsigned char *ptr = (unsigned char *) (note + 1) + 4; @@ -78,9 +93,15 @@ _dl_process_cet_property_note (struct link_map *l, unsigned int type = *(unsigned int *) ptr; unsigned int datasz = *(unsigned int *) (ptr + 4); + /* Property type must be in ascending order. */ + if (type < last_type) + return; + ptr += 8; if ((ptr + datasz) > ptr_end) - break; + return; + + last_type = type; if (type == GNU_PROPERTY_X86_FEATURE_1_AND) { @@ -89,14 +110,18 @@ _dl_process_cet_property_note (struct link_map *l, we stop the search regardless if its size is correct or not. There is no point to continue if this note is ill-formed. */ - if (datasz == 4) - { - unsigned int feature_1 = *(unsigned int *) ptr; - if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT)) - l->l_cet |= lc_ibt; - if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) - l->l_cet |= lc_shstk; - } + if (datasz != 4) + return; + + feature_1 = *(unsigned int *) ptr; + + /* Keep searching for the next GNU property note + generated by the older linker. */ + break; + } + else if (type > GNU_PROPERTY_X86_FEATURE_1_AND) + { + /* Stop since property type is in ascending order. */ return; } @@ -112,6 +137,12 @@ _dl_process_cet_property_note (struct link_map *l, + ELF_NOTE_NEXT_OFFSET (note->n_namesz, note->n_descsz, align)); } + + /* We get here only if there is one or no GNU property note. */ + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT)) + l->l_cet |= lc_ibt; + if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) + l->l_cet |= lc_shstk; #endif } diff --git a/sysdeps/x86/link_map.h b/sysdeps/x86/link_map.h index ef1206a9d2..9367ed0889 100644 --- a/sysdeps/x86/link_map.h +++ b/sysdeps/x86/link_map.h @@ -19,8 +19,9 @@ /* If this object is enabled with CET. */ enum { - lc_none = 0, /* Not enabled with CET. */ - lc_ibt = 1 << 0, /* Enabled with IBT. */ - lc_shstk = 1 << 1, /* Enabled with STSHK. */ + lc_unknown = 0, /* Unknown CET status. */ + lc_none = 1 << 0, /* Not enabled with CET. */ + lc_ibt = 1 << 1, /* Enabled with IBT. */ + lc_shstk = 1 << 2, /* Enabled with STSHK. */ lc_ibt_and_shstk = lc_ibt | lc_shstk /* Enabled with both. */ - } l_cet:2; + } l_cet:3; |