sanitizer_tls_get_addr.cc revision 2d1fdb26e458c4ddc04155c1d421bced3ba90cd0
1c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath//===-- sanitizer_tls_get_addr.cc -----------------------------------------===// 2c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 3c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// The LLVM Compiler Infrastructure 4c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 5c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// This file is distributed under the University of Illinois Open Source 6c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// License. See LICENSE.TXT for details. 7c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 8c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath//===----------------------------------------------------------------------===// 9c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 10c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// Handle the __tls_get_addr call. 11c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// 12c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath//===----------------------------------------------------------------------===// 13c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 14c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath#include "sanitizer_tls_get_addr.h" 15c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 16c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath#include "sanitizer_flags.h" 17c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath#include "sanitizer_platform_interceptors.h" 18c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 19c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathnamespace __sanitizer { 20c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath#if SANITIZER_INTERCEPT_TLS_GET_ADDR 21c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 22c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// The actual parameter that comes to __tls_get_addr 23c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// is a pointer to a struct with two words in it: 24c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstruct TlsGetAddrParam { 25c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr dso_id; 26c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr offset; 27c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath}; 28c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 29c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// Glibc starting from 2.19 allocates tls using __signal_safe_memalign, 30c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// which has such header. 31c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstruct Glibc_2_19_tls_header { 32c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr size; 33c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr start; 34c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath}; 35c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 36c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// This must be static TLS 37c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath__attribute__((tls_model("initial-exec"))) 38c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstatic __thread DTLS dtls; 39c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 40c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// Make sure we properly destroy the DTLS objects: 41c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath// this counter should never get too large. 42c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstatic atomic_uintptr_t number_of_live_dtls; 437faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez 44c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstatic const uptr kDestroyedThread = -1; 45c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 46c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstatic inline void DTLS_Deallocate(DTLS::DTV *dtv, uptr size) { 47c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (!size) return; 48c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath VPrintf(2, "__tls_get_addr: DTLS_Deallocate %p %zd\n", dtv, size); 49c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath UnmapOrDie(dtv, size * sizeof(DTLS::DTV)); 50c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath atomic_fetch_sub(&number_of_live_dtls, 1, memory_order_relaxed); 51c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath} 52c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 53c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathstatic inline void DTLS_Resize(uptr new_size) { 54c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (dtls.dtv_size >= new_size) return; 55c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath new_size = RoundUpToPowerOfTwo(new_size); 56c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath new_size = Max(new_size, 4096UL / sizeof(DTLS::DTV)); 57c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath DTLS::DTV *new_dtv = 58c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath (DTLS::DTV *)MmapOrDie(new_size * sizeof(DTLS::DTV), "DTLS_Resize"); 597faaa9f3f0df9d23790277834d426c3d992ac3baCarlos Hernandez uptr num_live_dtls = 60c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath atomic_fetch_add(&number_of_live_dtls, 1, memory_order_relaxed); 61c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath VPrintf(2, "__tls_get_addr: DTLS_Resize %p %zd\n", &dtls, num_live_dtls); 62c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath CHECK_LT(num_live_dtls, 1 << 20); 63c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr old_dtv_size = dtls.dtv_size; 64c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath DTLS::DTV *old_dtv = dtls.dtv; 65c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (old_dtv_size) 66c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath internal_memcpy(new_dtv, dtls.dtv, dtls.dtv_size * sizeof(DTLS::DTV)); 67c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dtls.dtv = new_dtv; 68c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dtls.dtv_size = new_size; 69c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (old_dtv_size) 70c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath DTLS_Deallocate(old_dtv, old_dtv_size); 71c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath} 72c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 73c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathvoid DTLS_Destroy() { 74c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (!common_flags()->intercept_tls_get_addr) return; 75c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath VPrintf(2, "__tls_get_addr: DTLS_Destroy %p %zd\n", &dtls, dtls.dtv_size); 76c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr s = dtls.dtv_size; 77c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath dtls.dtv_size = kDestroyedThread; // Do this before unmap for AS-safety. 78c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath DTLS_Deallocate(dtls.dtv, s); 79c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath} 80c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath 81c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamathvoid DTLS_on_tls_get_addr(void *arg_void, void *res) { 82c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (!common_flags()->intercept_tls_get_addr) return; 83c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath TlsGetAddrParam *arg = reinterpret_cast<TlsGetAddrParam *>(arg_void); 84c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr dso_id = arg->dso_id; 85c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (dtls.dtv_size == kDestroyedThread) return; 86c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath DTLS_Resize(dso_id + 1); 87c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath if (dtls.dtv[dso_id].beg) 88c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath return; 89c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr tls_size = 0; 90c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath uptr tls_beg = reinterpret_cast<uptr>(res) - arg->offset; 91c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath VPrintf(2, "__tls_get_addr: %p {%p,%p} => %p; tls_beg: %p; sp: %p " 92c981c48f5bc9aefeffc0bcb0cc3934c2fae179ddNarayan Kamath "num_live_dtls %zd\n", 93 arg, arg->dso_id, arg->offset, res, tls_beg, &tls_beg, 94 atomic_load(&number_of_live_dtls, memory_order_relaxed)); 95 if (dtls.last_memalign_ptr == tls_beg) { 96 tls_size = dtls.last_memalign_size; 97 VPrintf(2, "__tls_get_addr: glibc <=2.18 suspected; tls={%p,%p}\n", 98 tls_beg, tls_size); 99 } else if ((tls_beg % 4096) == sizeof(Glibc_2_19_tls_header)) { 100 // We may want to check gnu_get_libc_version(). 101 Glibc_2_19_tls_header *header = (Glibc_2_19_tls_header *)tls_beg - 1; 102 tls_size = header->size; 103 tls_beg = header->start; 104 VPrintf(2, "__tls_get_addr: glibc >=2.19 suspected; tls={%p %p}\n", 105 tls_beg, tls_size); 106 } else { 107 VPrintf(2, "__tls_get_addr: Can't guess glibc version\n"); 108 // This may happen inside the DTOR of main thread, so just ignore it. 109 tls_size = 0; 110 } 111 dtls.dtv[dso_id].beg = tls_beg; 112 dtls.dtv[dso_id].size = tls_size; 113} 114 115void DTLS_on_libc_memalign(void *ptr, uptr size) { 116 if (!common_flags()->intercept_tls_get_addr) return; 117 VPrintf(2, "DTLS_on_libc_memalign: %p %p\n", ptr, size); 118 dtls.last_memalign_ptr = reinterpret_cast<uptr>(ptr); 119 dtls.last_memalign_size = size; 120} 121 122DTLS *DTLS_Get() { return &dtls; } 123 124#else 125void DTLS_on_libc_memalign(void *ptr, uptr size) {} 126void DTLS_on_tls_get_addr(void *arg, void *res) {} 127DTLS *DTLS_Get() { return 0; } 128void DTLS_Destroy() {} 129#endif // SANITIZER_INTERCEPT_TLS_GET_ADDR 130 131} // namespace __sanitizer 132