TRust: A Compilation Framework for In-process Isolation to Protect Safe Rust against Untrusted Code

Rust was invented to help developers build highly safe systems. It comes with a variety of programming constructs that put emphasis on safety and control of memory layout. Rust enforces strict discipline about a type system and ownership model to enable compile-time checks of all spatial and temporal safety errors. Despite this advantage in security, the restrictions imposed by Rust???s type system make it difficult or inefficient to express certain designs or computations. To ease or simplify their programming, developers thus often include untrusted code from unsafe Rust or external libraries written in other languages. Sadly, the programming practices embracing such untrusted code for flexibility or efficiency subvert the strong safety guarantees by safe Rust. This paper presents TRUST, a compilation framework which against untrusted code present in the program, provides trustworthy protection of safe Rust via in-process isolation. Its main strategy is allocating objects in an isolated memory region that is accessible to safe Rust but restricted from being written by the untrusted. To enforce this, TRUST employs software fault isolation and x86 protection keys. It can be applied directly to any Rust code without requiring manual changes. Our experiments reveal that TRUST is effective and efficient, incurring runtime overhead of only 7.55% and memory overhead of 13.30% on average when running 11 widely used crates in Rust

Enhancing a Lock-and-Key Scheme With MTE to Mitigate Use-After-Frees

Preventing Use-After-Free (UAF) bugs is crucial to ensure temporal memory safety. Against UAF attacks, much research has adopted a well-known approach, lock-and-key, in which unique, disposable locks and keys are first assigned respectively to objects and pointers, and then on every memory access, checked for a match. Attention has been drawn again to this approach by recent work that capitalizes on a vast abundance of virtual address (VA) space in the lock assignment, thus being able to prevent UAFs in stripped binary. However, as this VA-based lock-and-key scheme tends to rapidly consume virtual space, it is likely to suffer from high performance overhead. In this paper, we propose a new scheme, called the VA tagging, whose goal is to tackle this performance problem with the support of the Memory Tagging Architecture (MTA) introduced in several commodity processors. In our scheme, the original VA-based locks are augmented with tags of MTA. As a VA-based lock can be assigned to multiple objects with different tags, the same VA is reused for many objects without compromising temporal safety. We have observed in our experiments that this tagging scheme lowers the VA consumption rate drastically by one order of magnitude. We implement a light-weight memory allocator, Vatalloc, by modifying existing allocators, dlmalloc and jemalloc, to employ the VA tagging scheme for efficient prevention of UAFs. Our evaluation shows that Vatalloc with allocator modifications only incurs 1.70% (on dlmalloc) and 3.05% (on jemalloc) of runtime overhead without considering performance degradation of MTE. As a result of simulating the tagging architecture assuming the worst-case, postulating MTE precise trapping mode incurs performance overhead of 30.9% based on dlmalloc, and 25.5% based on jemalloc. If imprecise mode is assumed, the slowdown is measured 16.9% for dlmalloc and 12.0% for jemalloc respectively. Vatalloc only incurs 19.0% and 3.0% memory overhead for dlmalloc and jemalloc respectively

Patient-reported outcome, perception and satisfaction after laparoscopic cholecystectomy in Kigali, Rwanda.

peer reviewed[en] BACKGROUND: Laparoscopic surgery is the gold standard for many abdominal surgeries. Laparoscopic programs in low- and middle-income countries (LMICs) and in sub-Saharan Africa face many constraints, although its use is safe, feasible, and clinically beneficial. The authors assessed patient-reported outcomes and the experience of patients operated on at the University Teaching Hospital of Kigali (CHUK). METHODS: This is a retrospective cross-sectional study combining medical data from medical files and information collected from telephone calls to 288 patients who underwent laparoscopic cholecystectomy at CHUK from January 2015 to December 2020. RESULTS: Among 446 laparoscopic surgeries performed at CHUK over 6 years, cholecystectomies accounted for 64.6 % of cases (288/446). Postoperative complications and mortality after laparoscopic cholecystectomy were low, respectively 1.7 % and 0.7 %, while the median length of stay was 3 days. About 74 % of surveyed patients had never heard of laparoscopic surgery prior to their procedure. Knowledge of laparoscopic surgery was associated with patient education level (p 90 % of patients consider laparoscopic surgery as the best surgical approach in Rwanda, and for this reason they declared to be ready to promote this new technology despite its higher cost. However, patients reported some weaknesses and made recommendations for improving public awareness of laparoscopy and its benefits, patient-provider relationships, training of surgical workforce, laparoscopic equipment, and infrastructure. CONCLUSION: Laparoscopic cholecystectomy can be performed with a low rate of postoperative complications in a resource-limited setting like Rwanda. Patient satisfaction was high, but efforts should be made to improve public awareness of laparoscopic surgery, improve surgical capacity, laparoscopic equipment, and infrastructure

Spatio-temporal genetic structure of Anopheles gambiae in the Northwestern Lake Victoria Basin, Uganda: implications for genetic control trials in malaria endemic regions

Abstract Background Understanding population genetic structure in the malaria vector Anopheles gambiae (s.s.) is crucial to inform genetic control and manage insecticide resistance. Unfortunately, species characteristics such as high nucleotide diversity, large effective population size, recent range expansion, and high dispersal ability complicate the inference of genetic structure across its range in sub-Saharan Africa. The ocean, along with the Great Rift Valley, is one of the few recognized barriers to gene flow in this species, but the effect of inland lakes, which could be useful sites for initial testing of genetic control strategies, is relatively understudied. Here we examine Lake Victoria as a barrier between the Ugandan mainland and the Ssese Islands, which lie up to 60 km offshore. We use mitochondrial DNA (mtDNA) from populations sampled in 2002, 2012 and 2015, and perform Bayesian cluster analysis on mtDNA combined with microsatellite data previously generated from the same 2002 mosquito DNA samples. Results Hierarchical analysis of molecular variance and Bayesian clustering support significant differentiation between the mainland and lacustrine islands. In an mtDNA haplotype network constructed from this and previous data, haplotypes are shared even between localities separated by the Rift Valley, a result that more likely reflects retention of shared ancestral polymorphism than contemporary gene flow. Conclusions The relative genetic isolation of An. gambiae on the Ssese Islands, their small size, level terrain and ease of access from the mainland, the relative simplicity of the vectorial system, and the prevalence of malaria, are all attributes that recommend these islands as possible sites for the testing of genetic control strategies

Data from: Spatio-temporal genetic structure of Anopheles gambiae in the Northwestern Lake Victoria Basin, Uganda: implications for genetic control trials in malaria endemic regions

Background: Understanding population genetic structure in the malaria vector Anopheles gambiae (s.s.) is crucial to inform genetic control and manage insecticide resistance. Unfortunately, species characteristics such as high nucleotide diversity, large effective population size, recent range expansion, and high dispersal ability complicate the inference of genetic structure across its range in sub-Saharan Africa. The ocean, along with the Great Rift Valley, is one of the few recognized barriers to gene flow in this species, but the effect of inland lakes, which could be useful sites for initial testing of genetic control strategies, is relatively understudied. Here we examine Lake Victoria as a barrier between the Ugandan mainland and the Ssese Islands, which lie up to 60 km offshore. We use mitochondrial DNA (mtDNA) from populations sampled in 2002, 2012 and 2015, and perform Bayesian cluster analysis on mtDNA combined with microsatellite data previously generated from the same 2002 mosquito DNA samples. Results: Hierarchical analysis of molecular variance and Bayesian clustering support significant differentiation between the mainland and lacustrine islands. In an mtDNA haplotype network constructed from this and previous data, haplotypes are shared even between localities separated by the Rift Valley, a result that more likely reflects retention of shared ancestral polymorphism than contemporary gene flow. Conclusions: The relative genetic isolation of An. gambiae on the Ssese Islands, their small size, level terrain and ease of access from the mainland, the relative simplicity of the vectorial system, and the prevalence of malaria, are all attributes that recommend these islands as possible sites for the testing of genetic control strategies

Patient-reported outcome, perception and satisfaction after laparoscopic cholecystectomy in Kigali, Rwanda

Background: Laparoscopic surgery is the gold standard for many abdominal surgeries. Laparoscopic programs in low- and middle-income countries (LMICs) and in sub-Saharan Africa face many constraints, although its use is safe, feasible, and clinically beneficial. The authors assessed patient-reported outcomes and the experience of patients operated on at the University Teaching Hospital of Kigali (CHUK). Methods: This is a retrospective cross-sectional study combining medical data from medical files and information collected from telephone calls to 288 patients who underwent laparoscopic cholecystectomy at CHUK from January 2015 to December 2020. Results: Among 446 laparoscopic surgeries performed at CHUK over 6 years, cholecystectomies accounted for 64.6 % of cases (288/446). Postoperative complications and mortality after laparoscopic cholecystectomy were low, respectively 1.7 % and 0.7 %, while the median length of stay was 3 days. About 74 % of surveyed patients had never heard of laparoscopic surgery prior to their procedure. Knowledge of laparoscopic surgery was associated with patient education level (p 90 % of patients consider laparoscopic surgery as the best surgical approach in Rwanda, and for this reason they declared to be ready to promote this new technology despite its higher cost. However, patients reported some weaknesses and made recommendations for improving public awareness of laparoscopy and its benefits, patient-provider relationships, training of surgical workforce, laparoscopic equipment, and infrastructure. Conclusion: Laparoscopic cholecystectomy can be performed with a low rate of postoperative complications in a resource-limited setting like Rwanda. Patient satisfaction was high, but efforts should be made to improve public awareness of laparoscopic surgery, improve surgical capacity, laparoscopic equipment, and infrastructure

Malaria in Uganda: challenges to control on the long road to elimination: I. Epidemiology and current control efforts.

Malaria remains one of the leading health problems of the developing world, and Uganda bears a particularly large burden from the disease. Our understanding is limited by a lack of reliable data, but it is clear that the prevalence of malaria infection, incidence of disease, and mortality from severe malaria all remain very high. Uganda has made progress in implementing key malaria control measures, in particular distribution of insecticide-impregnated bednets, indoor residual spraying of insecticides, utilization of artemisinin-based combination therapy to treat uncomplicated malaria, and provision of intermittent preventive therapy for pregnant women. However, despite enthusiasm regarding the potential for the elimination of malaria in other areas, there is no convincing evidence that the burden of malaria has decreased in Uganda in recent years. Major challenges to malaria control in Uganda include very high malaria transmission intensity, inadequate health care resources, a weak health system, inadequate understanding of malaria epidemiology and the impact of control interventions, increasing resistance of parasites to drugs and of mosquitoes to insecticides, inappropriate case management, inadequate utilization of drugs to prevent malaria, and inadequate epidemic preparedness and response. Despite these challenges, prospects for the control of malaria have improved, and with attention to underlying challenges, progress toward the control of malaria in Uganda can be expected

Can population differences explain the contrasting results of the Mwanza, Rakai, and Masaka HIV/sexually transmitted disease intervention trials?: A modeling study.

OBJECTIVE: To determine whether population differences can explain the contrasting impacts on HIV observed in the Mwanza trial of sexually transmitted disease (STD) syndromic treatment (ST), the Rakai trial of STD mass treatment (MT), and the Masaka trial of information, education, and communication (IEC) with and without ST as well as to predict the effectiveness of each intervention strategy in each population. METHODS: Stochastic modeling of the transmission of HIV and 6 STDs was used with parameters fitted to demographic, sexual behavior, and epidemiological data from the trials and general review of STD/HIV biology. RESULTS: The baseline trial populations could be simulated by assuming higher risk behavior in Uganda compared with Mwanza in the 1980s, followed by reductions in risk behavior in Uganda preceding the trials. In line with trial observations, the projected HIV impacts were larger for the ST intervention in Mwanza than for the MT intervention in Rakai or the IEC and IEC + ST interventions in Masaka. All 4 simulated intervention strategies were more effective in reducing incidence of HIV infection in Mwanza than in either Rakai or Masaka. CONCLUSIONS: Population differences in sexual behavior, curable STD rates, and HIV epidemic stage can explain most of the contrast in HIV impact observed between the 3 trials. This study supports the hypothesis that STD management is an effective HIV prevention strategy in populations with a high prevalence of curable STDs, particularly in an early HIV epidemic